As filed with the Securities and Exchange Commission on September 6, 2001
                                                                File No. 333-

================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                              ---------------------
                                    FORM S-3
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                             ----------------------
<TABLE>
<CAPTION>
                               APHTON CORPORATION
             (Exact name of registrant as specified in its charter)

<S>                                        <C>                              <C>
     Delaware                                                                    95-3640931
(State or other jurisdiction                  444 Brickell Avenue             (I.R.S. Employer
of incorporation or organization)                Suite 51-507               Identification Number)
                                           Miami, Florida  33131-2492
                                                (305) 374-7338
</TABLE>
               (Address, including zip code, and telephone number,
        including area code, of registrant's principal executive offices)
                           ---------------------------
                                 Philip C. Gevas
                 Chairman, President and Chief Executive Officer
                               Aphton Corporation
                               444 Brickell Avenue
                                  Suite 51-507
                            Miami, Florida 33131-2492
                                 (305) 374-7338
           (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                   Copies to:
                             Jonathan E. Kahn, Esq.
                                White & Case LLP
                           1155 Avenue of the Americas
                            New York, New York 10036
                           ---------------------------
         Approximate date of commencement of proposed sale to the public: From
time to time after this Registration Statement becomes effective.
         If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. |_|
         If any of the securities being registered on this Form are to be
offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, other than securities offered only in connection with
dividend or interest reinvestment plans, check the following box. |X|
         If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. |_|
         If this Form is a post-effective amendment filed pursuant to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act registration statement number of the earlier effective registration
statement for the same offering. |_|
         If delivery of the prospectus is expected to be made pursuant to Rule
434, please check the following box. |_|

<TABLE>
<CAPTION>

                                                 CALCULATION OF REGISTRATION FEE
===========================================================================================================================
                                                          PROPOSED MAXIMUM          PROPOSED MAXIMUM            AMOUNT OF
         TITLE OF SECURITIES               AMOUNT TO      AGGREGATE PRICE          AGGREGATE OFFERING         REGISTRATION
          TO BE REGISTERED               BE REGISTERED    PER SHARE (1)(2)              PRICE(1)                  FEE (2)
---------------------------------------------------------------------------------------------------------------------------
<S>                                        <C>                 <C>                   <C>                        <C>
Common Stock, $.001 par value              1,187,503           $13.32                $15,817,539.96             $3,954.38
===========================================================================================================================

</TABLE>

(1) Estimated solely for the purpose of calculating the registration fee in
accordance with Rule 457 of the Securities Act of 1933.
(2) Based on average of the high and low prices of the common stock reported on
the Nasdaq National Market System on September 4, 2001.

                             ----------------------

     The Registrant hereby amends this registration statement on such date or
dates as may be necessary to delay its effective date until the Registrant shall
file a further amendment which specifically states that this Registration
Statement shall thereafter become effective in accordance with Section 8(a) of
the Securities Act of 1933 or until the Registration Statement shall become
effective on such date as the Commission, acting pursuant to said Section 8(a),
may determine.
================================================================================

<PAGE>

THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. THESE
SECURITIES MAY NOT BE SOLD UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER
TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER TO BUY THESE
SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.



                 SUBJECT TO COMPLETION, DATED SEPTEMBER __, 2001

           1,187,503 Shares of Common Stock, Par Value $.001 per Share

                               Aphton Corporation



         This prospectus relates to an offering of up to 1,187,503 shares of
common stock of Aphton Corporation, a Delaware corporation. The shares of common
stock (which we refer to as the Shares) may or may not be offered for sale from
time to time by the selling stockholders. We will not receive any of the
proceeds from the sale of the Shares.

         The Shares are listed on the Nasdaq National Market under the symbol
"APHT." On September 4, 2001, the last reported sale price of our common stock
reported on Nasdaq was $13.40.

         We have been advised by the selling stockholders that they may or may
not sell all or a portion of the Shares from time to time on Nasdaq. They may
also make private sales of Shares to purchasers directly. Alternatively, they
may from time to time offer the Shares through underwriters, brokers, dealers or
agents, who may receive compensation in the form of underwriting discounts,
commissions or concessions.

         Investing in the Shares involves risks. See "Risk Factors" beginning on
page 2 of this prospectus for a discussion of certain factors you should
consider before you buy Shares.

                              ---------------------

         Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

                              ---------------------



                The date of this prospectus is          , 2001

<PAGE>

                                TABLE OF CONTENTS

ABOUT THIS PROSPECTUS.........................................................1

THE COMPANY...................................................................1

RISK FACTORS..................................................................2

FORWARD-LOOKING STATEMENTS....................................................9

USE OF PROCEEDS...............................................................9

THE SELLING STOCKHOLDERS.....................................................10

PLAN OF DISTRIBUTION.........................................................12

LEGAL MATTERS................................................................14

EXPERTS......................................................................14

WHERE YOU CAN FIND MORE INFORMATION..........................................15

INCORPORATION OF DOCUMENTS BY REFERENCE......................................15



<PAGE>

                              ABOUT THIS PROSPECTUS


         This prospectus is part of a registration statement on Form S-3 that we
filed with the Securities and Exchange Commission using a "shelf" registration
process. Under this process, the selling stockholders may, from time to time,
sell up to 1,187,503 Shares in one or more offerings. This prospectus does not
contain all of the information included in the registration statement and the
exhibits thereto. Statements included in this prospectus as to the contents of
any contract or other document that is filed as an exhibit to the registration
statement are not necessarily complete and you should refer to that agreement or
document for a complete description of these matters. You should read both this
prospectus and any prospectus supplement, together with the additional
information described in this prospectus under the heading "Where You Can Find
More Information."


                                   THE COMPANY


         Aphton Corporation is a biopharmaceutical company in advanced stage,
pivotal Phase III clinical trials. We are developing products using our
innovative vaccine-like technology for neutralizing, and removing from
circulation, hormones that participate in gastrointestinal system and
reproductive system cancer and non-cancer diseases. We are also developing
products for neutralizing hormones to prevent pregnancy. We have strategic
alliances with Aventis Pasteur (NYSE: AVE), GlaxoSmithKline (NYSE: GSK),
Schering Plough Animal Health (NYSE: SGP) and the World Health Organization
(WHO). Our Web page, describing the company, our technology, products,
strategic alliances and news releases can be visited at: www.aphton.com. The Web
site is not a part of this prospectus.

         We have financed our operations since inception through the sale of our
equity securities and, to a lesser extent, operating revenues from R&D limited
partnerships to conduct research and development. These funds provided us with
the resources to acquire staff, construct our research and development
facilities, acquire capital equipment and to finance technology and product
development, manufacturing and clinical trials.

         On August 27, 2001, we completed a private placement of 1,187,503
shares of common stock at a price of $12.00 per share. The proceeds of the
financing will be used to fund our ongoing clinical trials and operations. We
are currently conducting a pivotal Phase III clinical trial with patients with
advanced pancreatic cancer in the U.S. and in Europe. We are conducting
additional pivotal trials with our anti-gastrin vaccine for chemo-refractory
patients with colorectal cancer and for patients diagnosed with advanced stomach
cancer. A fourth trial is underway in the U.S. and Europe using our GnRH
pharmaccine for hormone refractory prostate cancer patients.

         We anticipate that our existing capital resources, which are composed
primarily of cash and short-term cash investments, including the proceeds of our
private placements and interest thereon, would enable us to maintain our
currently planned operations substantially into the year 2002. Our working
capital and capital requirements will depend on numerous factors, including the
following: the progress of our research and development program, preclinical
testing and


<PAGE>

clinical trials; the timing and cost of obtaining regulatory approvals; the
levels of resources that we devote to product development, manufacturing and
marketing capabilities; technological advances; competition; and collaborative
arrangements or strategic alliances with other drug companies, including the
further development, manufacturing and marketing of certain of our products and
our ability to obtain funds from such strategic alliances or from other sources.


                                  RISK FACTORS


         If you purchase our Shares, you will take on a financial risk. In
deciding whether to invest, you should carefully consider the following factors,
the information contained in this prospectus and the other information to which
we have referred you. Additional risks and uncertainties not presently known to
us or that we currently consider not material may also impair our business
operations. If any of the following risks actually occur, our business,
financial condition or results of operations could be materially adversely
affected. In such case, the trading price of our common stock could decline, and
you may lose all or part of your investment.

         Our potential products are in the early stages of product development.
All of our potential products are in research and development, and we have
generated no revenues from product sales. Our most advanced potential product,
an immunogen for the treatment of pancreatic cancer, is in Phase III pivotal
trials in the United States and Europe. Our other current potential products,
for the treatment of stomach cancer, colorectal cancer, gastroesophageal reflux
disease (or GERD), chronic peptic ulcers, breast cancer, endometriosis and
prostate cancer are at the same or even earlier phases of development. All of
our potential products will require significant additional research and
development and expensive, extensive, time consuming clinical testing prior to
commercial use. Accordingly, we do not expect to derive revenues from these
products for a number of years, if at all. We can offer no assurance that these
potential products will be successfully developed into immunogens that can be
administered to humans or that any such immunogen will prove safe and effective
in clinical trials or cost-effective to manufacture and administer. In addition,
we can offer no assurance that we will not encounter problems in clinical trials
that will cause us to delay or suspend a clinical trial, that such of our
products as are currently under development will be completed successfully
within any specified time period, if at all, that such testing will show such
products to be safe or effective or that any of our products will receive
regulatory approval. Further, if any of our products do receive required
regulatory approval, we can offer no assurance that we will be capable of
producing those products in commercial quantities at reasonable costs or that
those products will be accepted by the marketplace.

         We expect to continue to incur operating losses in the next several
years. We have experienced significant operating losses since our inception in
1981 and expect to continue to incur substantial operating losses for at least
the next several years. We expect losses to increase as a result of the expenses
associated with clinical testing and research and development. As of June 30,
2001, we had an accumulated deficit of approximately $79 million. Our ability to
achieve profitability depends upon our ability, alone or through relationships
with third parties, to successfully develop our technology and products, to
obtain required regulatory approvals and to

                                      -2-

<PAGE>

manufacture, market and sell such products. There can be no assurance that we
will ever have profitable operations or that profitability, if achieved, can be
sustained on an ongoing basis.

         We have never paid any dividends and do not expect to pay cash
dividends before significant product revenues, if any, are realized, if then.

         We have substantial capital requirements and we may not be able to
obtain additional financing. The development of our technology and products will
require a commitment of substantial funds to conduct the costly and
time-consuming research and clinical trials necessary for such development. Our
future capital requirements will depend on many other factors including
continued scientific progress in the research and development (clinical trials)
of our products, our ability to collaborate with others for the manufacture,
marketing and sale of our products, the cost of regulatory approvals, the cost
of establishing, maintaining and enforcing intellectual property rights,
competing technological and market developments and changes in our existing
research relationships. Our net rate of expenditure during the two-year period
ended January 31, 2001 averaged approximately $1.1 million per month. We
anticipate, however, that the rate of expenditure will increase substantially as
we proceed through the Phase III clinical trials for our anti-gastrin immunogen
products. This rate of expenditure may increase further if we pursue preclinical
studies or clinical trials for our other products at a faster rate than we
currently anticipate. We believe that our current capital resources, which are
composed primarily of cash and cash equivalents, should be sufficient, barring
unforeseen circumstances, to fund our operating expenses and capital
requirements as currently planned into the year 2002.

         We may seek additional financing through collaborative arrangements or
through public or private equity or debt financings. There can be no assurance
that additional financing will be available on acceptable terms or at all. If we
raise additional funds by issuing equity securities, dilution to the interests
of stockholders may result. If adequate funds are not available, we may be
required to delay, reduce the scope of or eliminate one or more of our research
or development programs or to obtain funds through arrangements with
collaborative partners or others that may require us to relinquish rights to
certain of our technologies, potential products or products that we would
otherwise seek to develop or commercialize ourselves.

         Our different approach to disease treatment may not prove successful.
We believe that our products under development are based on an approach to
disease therapy and prevention which previously has not been used successfully
by any pharmaceutical or biotechnology company. We cannot offer any assurance
that we will successfully complete our product development efforts, that our
products will be proven to be safe and effective, that approval by the U.S. Food
and Drug Administration ("FDA") or any other applicable regulatory agency will
be obtained or that medical centers, hospitals, physicians or patients will
accept our products as readily as current drug therapies or other forms of
treatment. Undesirable and unintended side effects or unfavorable publicity
concerning any of our products or other products incorporating a similar
approach could limit or curtail commercial use of our products and could have an
adverse effect on our ability to obtain regulatory approvals and to achieve
physician and patient acceptance.

                                      -3-

<PAGE>

         The development of our products is subject to extensive regulation. The
research, preclinical development, clinical trials, manufacturing and marketing
of our products are subject to extensive regulation by numerous governmental
authorities in the United States and other countries. Clinical trials and
manufacturing and marketing of products will undergo rigorous testing and
approval processes by the FDA and equivalent foreign regulatory authorities,
including the Medicines Control Agency ("MCA") in the United Kingdom. The
process of obtaining FDA and other required regulatory approvals is lengthy and
expensive. The time required for FDA approval is uncertain, and typically takes
a number of years, depending on the type, complexity and novelty of the product.
Since certain of our products involve the application of new technologies and
are based on a new therapeutic approach, regulatory approvals may be obtained
more slowly than for products produced using more conventional technologies.
Additionally, we may encounter delays or disapprovals based upon additional
government regulation resulting from future legislation or administrative action
or changes in FDA or equivalent foreign regulatory policy made during the period
of product development and regulatory review.

         We may apply for MCA approval to commercialize our potential immunogen
for the treatment of one or more of the gastrointestinal system cancers and
ulcerations previously described prior to applying for similar FDA approval.
Even if we obtain MCA approval, FDA approval would still be required prior to
marketing such a product in the United States. Although we have filed an
Investigational New Drug application ("IND") (a type of submission used to
ultimately obtain FDA approval to market a new drug) with the FDA and the FDA
has permitted us to proceed with clinical trials in the United States for
pancreatic cancer and for gastric cancer, the clinical trials will seek safety
data as well as efficacy data and will require substantial time and significant
funding. We cannot offer any assurance that clinical trials in the United
Kingdom or the United States or any other country will be fully and successfully
completed within any specified time period, if at all, with respect to any of
our products. Furthermore, we, the MCA or the FDA may suspend clinical trials at
any time if it is determined that the participants in such trials are being
exposed to unacceptable health risks. We cannot offer assurance that approval
for any products we develop will be granted by applicable regulatory agencies on
a timely basis, if at all, or, if granted, that the approval will cover all the
clinical indications for which we are seeking approval or will not contain
significant limitations in the form of warnings, precautions or
contraindications with respect to conditions of use. Any delay in obtaining, or
failure to obtain, such approvals would adversely affect our ability to generate
product revenue. Failure to comply with the applicable regulatory requirements
can, among other things, result in fines, suspensions of regulatory approvals,
product recalls, operating restrictions and criminal prosecution. In addition,
the marketing and manufacturing of drugs and biological products are subject to
continuing FDA review, and later discovery of previously unknown problems with a
product, its manufacture or its marketing may result in the FDA requiring
further clinical research or restrictions on the product or the manufacturer,
including withdrawal of the product from the market.

         The industry in which we operate is characterized by rapid
technological change and intense competition. The treatment of diseases such as
those to which our products are directed is subject to rapid, unpredictable and
significant change. Our products under development seek to address certain
cancers and diseases currently addressed, to some extent, by existing or

                                      -4-

<PAGE>

evolving products and technologies of other biotechnology and pharmaceutical
companies. Competition from other biotechnology companies, large pharmaceutical
companies and universities and other research institutions is intense and is
expected to increase. Many of these companies and institutions have
substantially greater resources, research and development staffs and facilities
than we do and have substantially greater experience in obtaining regulatory
approval, and in manufacturing and marketing pharmaceutical products. In
addition, other technologies may in the future be the basis of competitive
products. There can be no assurance that our competitors will not succeed in
developing technologies and products that are more effective than those we are
developing or that would render our technology and products obsolete or
noncompetitive.

         Our ability to enforce our patents and proprietary rights is uncertain.
Our success will depend in large part on our ability to obtain patents, both in
the United States and in other countries, maintain our unpatented trade secrets
and operate without infringing on the proprietary rights of others. The patent
positions of biotechnology and pharmaceutical companies can be highly uncertain
and involve complex legal and factual questions, and therefore the breadth and
enforceability of claims allowed in patents we have obtained cannot be
predicted.

         We hold issued patents and have pending patent applications and patent
applications in preparation. We can offer no assurance, however, that our
pending applications or patent applications in preparation or to be prepared
will be issued as patents. Additionally, our existing patents, patents pending
and patents that we may subsequently obtain will not necessarily preclude
competitors from developing products that can be marketed in competition with
products we have developed and thus would substantially lessen the value of our
proprietary rights. We intend to file additional patent applications, when
appropriate, relating to our technologies, improvements to our technologies and
specific products we may develop. We can offer no assurance that any issued,
pending or future patents will not be challenged, invalidated or circumvented,
or that the rights granted will provide proprietary protection or competitive
advantages to us. If any of our patents are invalidated or held to be
unenforceable, we could lose the protection of rights we believe to be valuable,
and our business could be materially and adversely affected.

         Our commercial success also will depend, in part, on our not infringing
patents issued to others. We can offer no assurance that our products will not
infringe on the patents or proprietary rights of others. We may be required to
obtain licenses to patents, patent applications or other proprietary rights of
others. We cannot assure that any such licenses would be made available on terms
acceptable to us, if at all. If we do not obtain such licenses, we could
encounter delays in product introductions while we attempt to design around such
patents, or the development, manufacture or sale of products requiring such
licenses could be precluded. We could incur substantial costs, including
diversion of management time, in defending ourselves in litigation brought
against us on such patents or in litigation in which we assert our patents
against another party, or in litigation brought by another party asserting its
patents against us. If our competitors prepare and file patent applications in
the United States that claim technology also claimed by us, we may have to
participate in interference proceedings declared by the U.S. Patent and
Trademark Office to determine priority of invention, which could result in
substantial financial costs to us and diversion of management attention, even if
the eventual outcome is

                                      -5-

<PAGE>

favorable to us. We believe there will continue to be significant litigation in
the industry regarding patent and other intellectual property rights.

         We also rely on trade secrets to protect our technology, especially
where patent protection is not believed to be appropriate or obtainable. Thus,
we protect our proprietary technology and processes, in part, by confidentiality
agreements with our employees, consultants and certain contractors. We can offer
no assurance that these agreements will not be breached, that we would have
adequate remedies for any breach, or that our trade secrets will not otherwise
become known or be independently discovered by competitors.

         We depend on others for manufacturing and marketing. We have no
manufacturing facilities for commercial production of our products under
development and have no experience in marketing, sales or distribution. We
intend to continue establishing arrangements with and relying on third parties,
including large pharmaceutical companies, to manufacture, market, sell and
distribute any product we develop. Although we believe that parties to any
future arrangements will have an economic incentive to successfully perform
their contractual responsibilities, the amount and timing of resources to be
dedicated to these activities will not be within our control. We can offer no
assurance that such parties will perform their obligations as expected, that we
will derive any revenues from such arrangements or that our reliance on others
for manufacturing products will not result in unforeseen problems with product
supply. Should we encounter delays or difficulties in establishing relationships
with manufacturers to produce, package and distribute any product we develop,
market introduction and subsequent sales of such products would be adversely
affected. Moreover, contract manufacturers that we may use must adhere to
current good manufacturing practice regulations enforced by the FDA through its
facilities inspection program. If these facilities cannot pass a pre-approval
plant inspection, any FDA pre-market approval of our potential products would be
adversely affected. Additionally, these manufacturers are subject to continual
review and periodic inspections by the FDA and discovery of previously unknown
problems with a manufacturer or facility may result in FDA restrictions which
could adversely affect the manufacture and marketing of our products.

         We depend on key personnel. We are dependent upon the services of our
senior management, none of whom are subject to an employment agreement with us.
We have not insured against the loss, due to death or disability, of any key
personnel. The loss of the services of any key personnel could have a material
adverse effect on us. Because of the specialized nature of our business, our
success also depends upon our ability to attract and retain highly qualified
scientists and other technical personnel. We face intense competition for such
persons and there can be no assurance that we will be able to attract or retain
such individuals.

         Future healthcare reforms may adversely affect our financial results.
The levels of revenues and profitability of biotechnology and pharmaceutical
companies, including Aphton, may be affected by the continuing efforts of
governmental and third-party payors to contain or reduce the costs of health
care through various means. For example, in certain foreign markets, pricing or
profitability of prescription pharmaceuticals is subject to government control.
In the United States, there have been, and we expect that there will continue to
be, a number of federal and state proposals to control health care costs. It is
uncertain what legislative proposals, if any, will be adopted or what actions
federal, state or third-party payors may take in response to any

                                      -6-

<PAGE>

health care reform proposals or legislation. We cannot predict the effect health
care reforms may have on our business, and no assurance can be given that any
such reforms will not have a material adverse effect on us. Further, to the
extent that such proposals or reforms have an adverse effect on the business,
financial condition and profitability of other biotechnology or pharmaceutical
companies that are prospective corporate partners for certain of our products,
our ability to commercialize our products may be adversely affected.

         Our success depends on third party reimbursement. Successful
commercialization of our products will depend in part on the availability of
adequate reimbursement from third-party health care payors, such as government
and private health insurers and other organizations. Third-party payors are
increasingly challenging the pricing of medical products and services.
Significant uncertainty exists as to the reimbursement status of newly approved
health care products. We can offer no assurance that any product that we succeed
in bringing to market will be eligible for reimbursement at a level which is
sufficient to enable us to achieve market acceptance of our products or to
maintain appropriate pricing. Without such reimbursement, the market for our
products may be limited. Significant reductions in insurance coverage also may
have an adverse affect on our future operations.

         We may be exposed to product liability claims and uninsured risk. The
use of any of our products, whether for commercial applications or during
pre-clinical or clinical trials, exposes us to an inherent risk of product
liability claims in the event such products cause injury or result in adverse
effects. Such liability might result from claims made directly by health care
institutions, contract laboratories or others selling or using such products. We
currently maintain product liability coverage against risks associated with
testing our potential products in clinical trials. Insurance coverage for
product liability, however, is becoming increasingly expensive and difficult to
obtain. There can be no assurance that insurance coverage will be available in
the future at an acceptable cost, if at all, or in sufficient amounts to protect
us against such liability. The obligation to pay any product liability claim in
excess of whatever insurance we are able to acquire could have a material
adverse effect on our business, financial condition and future prospects.

         Our business involves the use of hazardous materials that could expose
us to environmental liability. Our research and development activities involve
the controlled use of hazardous materials, chemicals, cultures and various
radioactive compounds. We are subject to federal, state and local laws and
regulations governing the use, generation, manufacture, storage, air emission,
effluent discharge, handling and disposal of such materials and certain waste
products. Although we believe that our safety procedures for handling and
disposing of such materials comply with the standards prescribed by such laws
and regulations, the risk of accidental contamination or injury from these
materials cannot be completely eliminated. In the event of such an accident, we
could be held liable for any damages that result and any such liability could
exceed our resources. We may be required to incur significant costs to comply
with environmental laws and regulations in the future. Current or future
environmental laws or regulations could materially adversely affect our
business, financial condition and results of operations.

                                      -7-

<PAGE>

         Ownership of our common stock is concentrated. As of August 30, 2001,
our officers and directors beneficially owned approximately 13% (19% on a
fully-diluted basis) of our outstanding common stock. Such a high level of
ownership by such persons may have a significant effect in delaying, deferring
or preventing any potential change in control of Aphton.

         The price of our common stock may be volatile. The market price of our
common stock, like that of securities of other biotechnology companies, has
fluctuated significantly in recent years and is likely to fluctuate in the
future. Announcements regarding scientific discoveries, technological
innovations, litigation, commercial products, patents or proprietary rights, the
progress of clinical trials, government regulation, public concern as to the
safety of drugs and reliability of our testing processes, and general market
conditions may have a significant effect on the market price of our common
stock. Fluctuations in financial performance from period to period also may have
a significant impact on the market price of our common stock.

         The exercise of outstanding warrants and rights to obtain additional
shares could dilute the value of the shares. As of August 30, 2001, we had
outstanding warrants to purchase approximately 2,700,000 shares of common stock
expiring at various dates through December 31, 2015, with exercise prices
ranging from $0.25 to $24.00 per share, all of which contain anti-dilution
provisions. The exercise of these warrants could result in dilution of the value
of the shares and the voting power represented thereby. We have granted
antidilution rights to the selling stockholders in the event that, at any time
before the first anniversary of the effective date of the registration statement
of which this prospectus forms a part, we issue shares of common stock or
rights, warrants, options or other securities or debt that are convertible into
or exchangeable for shares of common stock at a price per share less than $12.00
per share. We may issue additional capital stock, warrants and/or options to
raise capital in the future which could result in additional dilution.
Additionally, to attract and retain key personnel, we may issue additional
securities, including stock options.

         No prediction can be made as to the effect, if any, that future sales
of shares of common stock, or the availability of shares for future sale, will
have on the market price of the common stock prevailing from time to time. Sales
of substantial amounts of the common stock in the public market, or the
perception that such sales could occur, could adversely affect the market price
of the common stock and may make it more difficult for us to sell our equity
securities in the future at a time and price which we deem appropriate. Public
or private sales of substantial amounts of our common stock by persons or
entities that have exercised options and/or warrants could adversely affect the
prevailing market price of the common stock.

                                      -8-
<PAGE>

                           FORWARD-LOOKING STATEMENTS


         This prospectus, any prospectus supplement and the documents
incorporated by reference in this prospectus may contain "forward-looking
statements" within the meaning of Section 27A of the Securities Act of 1933, as
amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and
are intended to be covered by the safe harbor created by those sections. We have
based these forward-looking statements on our current expectations and
projections about future events.

         These statements include but are not limited to:

          o    expectations  as to the adequacy of our cash balances,  cash flow
               from  operations  and the  proceeds of  securities  issuances  to
               support our  operations  for specified  periods of time and as to
               the nature and level of cash expenditures;

          o    expectations as to the receipt and timing of regulatory clearance
               and approvals;

          o    expectations as to the development of our products, including our
               clinical research program; and

          o    statements as to anticipated reimbursement from third-party
               healthcare payors for our products.

         The forward-looking statements included or incorporated by reference in
these documents are based on the beliefs of our management as well as
assumptions made by us and information available to us on the date hereof. Our
actual results could differ materially from those anticipated in these
forward-looking statements as a result of various factors, including all the
risks discussed in "Risk Factors" and elsewhere in this prospectus.

         In addition, statements that use the terms "believe," "expect," "plan,"
"intend," "estimate," "anticipate" and similar expressions are intended to
identify forward-looking statements. All forward-looking statements in this
prospectus reflect our current views about future events and are based on
assumptions and are subject to risks and uncertainties that could cause our
actual results to differ materially from future results expressed or implied by
the forward-looking statements. Many of these factors are beyond our ability to
control or predict. You should not put undue reliance on any forward-looking
statements. Unless we are required to do so under U.S. federal securities laws
or other applicable laws, we do not intend to update or revise any
forward-looking statements. In evaluating our business, you should consider
carefully the factors set forth above under the heading "Risk Factors" in
addition to the other information set forth in this prospectus and incorporated
by reference in this prospectus.


                                 USE OF PROCEEDS


         We will not receive any proceeds from the sale of the Shares by the
selling stockholders, if they choose to sell some or all of the Shares.

                                      -9-

<PAGE>

                            THE SELLING STOCKHOLDERS


         We are registering the shares covered by this prospectus on behalf of
the selling stockholders named in the table below. We issued all of the shares
covered by this prospectus to the selling stockholders in a private placement
transaction. We are registering the shares to permit the selling stockholders to
resell the shares, if they choose to do so.

         The following table sets forth information known to us with respect to
beneficial ownership of our common stock as of September 4, 2001 by each selling
stockholder. The number of shares in the column "Shares Which May Be Offered"
represents all of the shares that each selling stockholder may offer under this
prospectus. The following table assumes that the selling stockholders sell all
of the shares registered for sale under this prospectus. The selling
stockholders may sell some, all or none of their shares. We do not know how long
the selling stockholders will hold the shares before selling them and we
currently have no agreements, arrangements or understandings with any of the
selling stockholders regarding the sale of any of the shares.

         Except as described in this prospectus, the selling stockholders have
not had a material relationship with us or any of our affiliates within the past
three years.

         In the following table, we have determined the number and percentage of
shares beneficially owned in accordance with Rule 13d-3 of the Securities
Exchange Act of 1934, as amended, and this information does not necessarily
indicate beneficial ownership for any other purpose. In determining the number
of shares beneficially owned by a person and the percentage ownership of that
person, we include any shares as to which the individual has sole or shared
voting power or investment power, as well as any shares of common stock subject
to options, warrants or other derivative securities held by that person that are
currently exercisable or exercisable within 60 days after September 4, 2001. We
do not consider these shares underlying options, warrants and other derivative
securities outstanding in computing the percentage ownership of any other
person, however. To our knowledge, the persons named in the table below have
sole voting and investment power with respect to all shares of common stock
shown as beneficially owned by them. The percentages of shares owned in the
following table are based on 17,386,996 shares of our common stock outstanding,
giving effect to the sale of 1,187,503 shares to the selling stockholders in the
private placement.

         The following table sets forth the number of Shares owned by the
selling stockholders as of the date of this prospectus.

<TABLE>
<CAPTION>
                                               Shares Beneficially       Shares Which
  Name                                       Owned Prior to Offering    May Be Offered
  ----                                       -----------------------    --------------

  <S>                                                <C>                    <C>
  Firstar Bank, N.A., custodian for
  Heartland Value Fund                               833,334                833,334
  Societe Generale                                    83,334                83,334
  Montrose Investments Ltd.                           83,334                83,334
  Vertical Ventures, LLC                              83,334                83,334
  SDS Merchant Fund, LP                               29,167                29,167
  Triton West Group                                   29,167                29,167
  DMG Legacy International Ltd.                       28,077                28,077
  DMG Institutional Fund LLC                           9,359                 9,359
  DMG Legacy Fund LLC                                  8,397                 8,397

</TABLE>

                                      -10-

<PAGE>

         All of the Shares being offered by this prospectus were acquired by the
selling stockholders under stock purchase agreements with us.

Registration rights of the selling stockholders

         We have agreed to maintain the effectiveness of the registration
statement of which this prospectus forms a part until the earliest to occur of
(i) the date that is two years after the effective date of the registration
statement of which this prospectus forms a part; (ii) such time as all of the
Shares have been sold by the selling stockholders; and (iii) such time as the
Shares are eligible for resale pursuant to Rule 144 under the Securities Act.

Antidilution rights of the selling stockholders

         Under the terms of the stock purchase agreements, if at any time before
the first anniversary of the effective date of the registration statement of
which this prospectus forms a part, we issue shares of common stock or rights,
warrants, options or other securities or debt that are convertible into or
exchangeable for shares of common stock, entitling any person to acquire shares
of common stock at a price per share less than $12.00 per share, then we must
issue to the selling stockholders an additional number of shares of common stock
equal to the number obtained by subtracting (a) the quotient obtained by
dividing $14,250,036 (the total purchase price paid by the selling stockholders)
by that lesser purchase price minus (b) 1,187,503 (the total number of shares
purchased by the selling stockholders). For example, if we issue shares of
common stock at a price of $10.00 per share during the next year, then we must
issue an aggregate of 237,500 shares of common stock to the selling
stockholders. The foregoing does not apply to the grant of options or warrants
or the issuance of additional securities to any employees or consultants under
any duly authorized stock option, restricted stock plan or stock purchase plan.

                                      -11-
<PAGE>

                              PLAN OF DISTRIBUTION


Who may sell the Shares and applicable restrictions

         We will not receive any of the proceeds from the sale of the Shares.
The selling stockholders may be offering and selling all Shares offered under
this prospectus or the selling stockholders may hold the shares indefinitely.

         The selling stockholders may also sell the Shares directly to market
makers acting as principals and/or broker-dealers acting as agents for
themselves or their customers. These broker-dealers may receive compensation in
the form of discounts, concessions or commissions from the selling stockholders
and/or the purchasers of Shares for whom such broker-dealers may act as agents
or to whom they sell as principal, or both. The compensation as to a particular
broker-dealer might be in excess of customary commissions. Market makers and
block purchasers purchasing the Shares will do so for their own account and at
their own risk. The selling stockholders and any broker-dealer or agent that
acts in connection with the sale of the Shares might be deemed to be
"underwriters" as that term is defined under the Securities Act, and any
commissions received by the broker-dealer or agent and any profit on the resale
of the Shares sold by them while acting as principals might be deemed to be
underwriting discounts or commissions under the Securities Act.

         The selling stockholders may sell all or any part of the Shares offered
by this prospectus through an underwriter. To our knowledge, none of the selling
stockholders has entered into any agreement with a prospective underwriter. If
any selling stockholder enters into such an agreement, the relevant details will
be set forth in a supplement to this prospectus.

         To comply with the securities laws of certain jurisdictions, the Shares
offered by this prospectus may need to be offered or sold in such jurisdictions
only through registered or licensed brokers or dealers.

Manner of sales

         The selling stockholders will act independently of us in making
decisions with respect to the manner and size of each sale. The selling
stockholders may sell the Shares from time to time in one or more of the
following types of transactions (which may include block transactions):

         o    on the Nasdaq National Market;

         o    in privately negotiated transactions;

         o    by selling to a broker or dealer as principal and resale by the
              broker or dealer for its own account;

         o    through underwriters or dealers who may receive compensation in
              the form of underwriting discounts, concessions or commissions;

         o    in block transactions to market makers or other purchasers at a
              price per share which may be below the then prevailing market
              price;

         o    through put or call options transactions relating to the Shares;

         o    through short sales of the Shares; or

         o    through a combination of the above methods of sale.

The sale price of the Shares may be the market price of our common stock
prevailing at the time of sale, a price related to the prevailing market price,
a negotiated price or such other price as the selling stockholders determine
from time to time. Each of the selling stockholders has the sole discretion not
to accept any purchase offer or make any sale of Shares if it deems the purchase
price to be unsatisfactory at any particular time.

         Under applicable rules and regulations under the Securities Exchange
Act of 1934, any person engaged in a distribution of Shares covered by this
prospectus may be limited in its ability to engage in market activities with
respect to such Shares. The selling stockholders, for example, will be subject
to applicable provisions of the Exchange Act and the rules and regulations under

                                      -12-

<PAGE>

it, including Rule 10b-5 and Regulation M. Regulation M may restrict certain
activities of the selling stockholders and limit the timing of purchases and
sales of any Shares by the selling stockholders. Furthermore, under Regulation
M, persons engaged in a distribution of securities are prohibited from
simultaneously engaging in market making and certain other activities with
respect to such securities for a specified period of time prior to the
commencement of such distributions, subject to specified exceptions or
exemptions.

Suspension of this offering

         Under the terms of the stock purchase agreements, we may require the
selling stockholders to suspend the availability of this prospectus and not to
effect any sales of Shares if we notify the selling stockholders of such a
suspension.

Prospectus delivery

         Because the selling stockholders may be deemed to be "underwriters"
within the meaning of Section 2(11) of the Securities Act, the selling
stockholders will be subject to the prospectus delivery requirements of the
Securities Act. At any time a particular offer of the Shares is made, a revised
prospectus or prospectus supplement, if required, will be distributed which will
set forth:

          o    the names of the selling stockholders and of any participating
               underwriters, broker-dealers or agents;

          o    the aggregate amount of securities being offered;

          o    the price at which the Shares were sold and other material terms
               of the offering;

          o    any discounts, commissions, concessions and other items
               constituting compensation from the selling stockholders and any
               discounts, commissions or concessions allowed or reallowed or
               paid to dealers; and

          o    that the participating broker-dealers did not conduct any
               investigation to verify the information in this prospectus or
               incorporated in this prospectus by reference.

The prospectus supplement or a post-effective amendment will be filed with the
SEC to reflect the disclosure of additional information with respect to the
distribution of the Shares.

Indemnification

         We have agreed to indemnify the selling stockholders against certain
liabilities, including liabilities arising under the Securities Act. The selling
stockholders may agree to indemnify any agent, dealer or broker-dealer that
participates in transactions involving sales of the Shares against certain
liabilities, including liabilities arising under the Securities Act.

                                      -13-

<PAGE>

Fees and expenses

         We have agreed to pay all costs, expenses and fees in connection with
the registration of the Shares. The selling stockholders will pay all
underwriting discounts and commissions and brokerage commissions and fees, if
any, payable with respect to the Shares.


                                  LEGAL MATTERS


         The validity of the Shares offered hereby will be passed upon by White
& Case LLP, New York, New York.


                                     EXPERTS


         The financial statements of Aphton Corporation as of and for the year
ended January 31, 2001 appearing in Aphton Corporation 's Annual Report on Form
10-K/A for the year ended January 31, 2001, have been audited by Ernst & Young
LLP, independent certified public accountants, as set forth in their report
thereon included therein and incorporated herein by reference. Such financial
statements are incorporated herein by reference in reliance upon such report
given on the authority of such firm as experts in accounting and auditing.

         The financial statements of Aphton Corporation as of January 31, 2000
and for each of the two years in the period ended January 31, 2000 incorporated
in this prospectus by reference to the Annual Report on Form 10-K/A for the year
ended January 31, 2001 have been so incorporated in reliance on the report of
PricewaterhouseCoopers LLP, independent accountants, given on the authority of
said firm as experts in auditing and accounting.

                                      -14-
<PAGE>


                       WHERE YOU CAN FIND MORE INFORMATION


         We are subject to the informational reporting requirements of the
Securities Exchange Act of 1934, and therefore we file reports, proxy statements
and other information with the SEC. You may read and copy these reports and
other information at the Public Reference Room maintained by the SEC at 450
Fifth Street, N.W., Washington, D.C. 20549. Please call the SEC at
1-800-SEC-0330 for further information on the public reference rooms. In
addition, the SEC maintains a home page on the Internet (http://www.sec.gov)
that contains certain reports and other information filed by us.


                     INCORPORATION OF DOCUMENTS BY REFERENCE


         The SEC allows us to "incorporate by reference" information from other
documents that we file with them, which means that we can disclose important
information by referring to those documents. The information incorporated by
reference is considered to be part of this prospectus, and information that we
file later with the SEC will automatically update and supersede this
information.

         This prospectus incorporates by reference the documents listed below.

          o    Annual Report on Form 10-K/A for the year ended January 31, 2001;
          o    Quarterly Report on Form 10-Q for the five months ended June 30,
               2001;
          o    Current Report on Form 8-K filed with the SEC on March 16, 2001;
               and
          o    The description of our common stock contained in our Registration
               Statement on Form 8-A, filed with the SEC on January 30, 1998.

         We also incorporate by reference additional documents that we may file
with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange
Act after the date of this prospectus and prior to the entire time all of the
Shares offered by this prospectus are sold. These include periodic reports, such
as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current
Reports on Form 8-K, as well as proxy statements.

         We undertake to provide without charge to each person, including any
beneficial owner, to whom a prospectus is delivered, a copy of these filings, at
no cost, by writing or telephoning us. Any requests should be directed to:

                               Aphton Corporation
                               444 Brickell Avenue
                                  Suite 51-507
                            Miami, Florida 33131-2492
                               Tel: (305) 374-7338

         You should rely only on the information incorporated by reference or
provided in this prospectus or any supplement. We have not authorized anyone
else to provide you with different information. You should not assume that the
information in this prospectus or any supplement is accurate as of any date
other than the date on the front of those documents.

                                      -15-

<PAGE>

                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.*

         SEC registration fee........................................    $ 3,954
         Legal fees and expenses.....................................     60,000
         Accounting fees and expenses................................      6,000
         Miscellaneous...............................................      1,046
                                                                          ------
                  Total..............................................    $71,000
                                                                          ======

* All amounts are estimated except for the SEC registration fee.

Item 15. Indemnification of Directors and Officers.

     Section 145 of the Delaware General Corporation Law (the "DGCL") permits
the Company to indemnify any person who is or was a director, officer, employee
and agent, or is or was serving at the request of the Company as a director,
officer, employee or agent of another company, partnership, joint venture, trust
or other enterprise (each an "Insider") against liability for each such
Insider's acts taken in his or her capacity as an Insider in a civil action,
suit or proceeding if such actions were taken in good faith and in a manner
which the Insider reasonably believed to be in or not opposed to the best
interests of the Company, and in a criminal action, suit or proceeding, if the
Insider had no reasonable cause to believe his or her conduct was unlawful,
including under certain circumstances, suits by or in the right of the Company
for any expenses, including attorneys' fees, judgments, fines and amounts paid
in settlements and for any liabilities which the Insider may have incurred in
consequence of such action, suit or proceeding under conditions stated in said
Section 145. The Company's Certificate of Incorporation and By-Laws provide that
the Company shall indemnify its directors and officers to the fullest extent
authorized by the DGCL; provided, that the Company will not be required to
indemnify any director or executive officer in connection with a proceeding
initiated by such person, with certain exceptions.

     As permitted by Section 102(b)(7) of the DGCL, Article NINTH of the
Company's Certificate of Incorporation provides that a director of the Company
will not be personally liable to the Company or its stockholders for monetary
damages for breach of fiduciary duty as a director, except for liability (i) for
any breach of the director's duty of loyalty to the Company or its stockholders,
(ii) for acts or omissions not in good faith or which involve intentional
misconduct or a knowing violation of law, (iii) under Section 174 of the DGCL,
as amended, which concerns unlawful payments of dividends, stock purchases or
redemption, or (iv) for any transaction from which the director derived an
improper personal benefit.

     The Company's Certificate of Incorporation permits the Company to secure
insurance on behalf of any director, officer, employee or agent of the Company
or another Company, partnership, joint venture, trust or other enterprise for
any liability arising out of his or her

                                      II-I

<PAGE>

actions in such capacity, regardless of whether the Company would have the power
to indemnify such person against such liability under the DGCL.

Item 16.        Exhibits.



   Exhibit No.                                      Description


     4.1  Certificate of Incorporation of Aphton Corporation (Incorporated by
          reference to Exhibit 3.1 to the registrant's Current Report on Form
          8-K filed on January 30, 1998).

     4.2  Specimen of Common Stock Certificate (Incorporated by reference to
          Exhibit 4.1 to the registrant's Registration Statement on Form 8-A
          filed on January 30, 1998).

     4.3  Form of Stock Purchase Agreement, dated August 27, 2001.

     5.1  Opinion of White & Case LLP.

     23.1 Consent of Ernst & Young LLP.

     23.2 Consent of PricewaterhouseCoopers LLP.

     23.3 Consent of White & Case LLP (included in their opinion filed as
          Exhibit 5.1 hereto).

     24.1 Power of Attorney (included on signature pages of this Registration
          Statement).



Item 17. Undertakings.

(a)  The undersigned Registrant hereby undertakes:

     (1)  To file, during any period in which offers or sales are being made, a
          post-effective amendment to this Registration Statement:

          (i)  To include any prospectus required by section 10(a)(3) of the
               Securities Act of 1933 (the "Securities Act");

          (ii) To reflect in the Prospectus any facts or events arising after
               the effective date of the Registration Statement (or the most
               recent post-effective amendment thereof) which, individually or
               in the aggregate, represent a fundamental change in the
               information set forth in the Registration Statement.
               Notwithstanding the foregoing, any increase or decrease in volume
               of securities offered (if the total dollar value of securities
               offered

                                      II-2
<PAGE>

               would not exceed that which was registered) and any deviation
               from the low or high end of the estimated maximum offering range
               may be reflected in the form of prospectus filed with the
               commission pursuant to Rule 424(b) if, in the aggregate, the
               changes in volume and price represent no more than a 20 percent
               change in the maximum aggregate offering price set forth in the
               "Calculation of Registration Fee" table in the effective
               registration statement;

          (iii) To include any material information with respect to the plan of
               distribution not previously disclosed in the registration
               statement or any material change to such information in the
               registration statement;

          provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
          apply if the information required to be included in a post-effective
          amendment by those paragraphs is contained in periodic reports filed
          with or furnished to the Commission by the Registrant pursuant to
          Section 13 or 15(d) of the Exchange Act that are incorporated by
          reference in the Registration Statement.

     (2)  That, for the purpose of determining any liability under the
          Securities Act, each such post-effective amendment shall be deemed to
          be a new registration statement relating to the securities offered
          therein, and the offering of such securities at that time shall be
          deemed to be the initial bona fide offering thereof.

     (3)  To remove from registration by means of a post-effective amendment any
          of the securities being registered which remain unsold at the
          termination of the offering.

(b)  The undersigned Registrant hereby undertakes that, for purposes of
     determining any liability under the Securities Act, each filing of the
     Registrant's annual report pursuant to Section 13(a) or 15(d) of the
     Exchange Act (and, where applicable, each filing of an employee benefit
     plan's annual report pursuant to Section 15(d) of the Exchange Act) that is
     incorporated by reference in the Registration Statement shall be deemed to
     be a new registration statement relating to the securities offered therein,
     and the offering of such securities at that time shall be deemed to be the
     initial bona fide offering thereof.

(h)  Insofar as indemnification for liabilities arising under the Securities Act
     may be permitted to directors, officers and controlling persons of the
     Registrant, the Registrant has been advised that in the opinion of the
     Commission such indemnification is against public policy as expressed in
     the Securities Act and is, therefore, unenforceable. In the event that a
     claim for indemnification against such liabilities (other than the payment
     by the Registrant of expenses incurred or paid by a director, officer or
     controlling person of the Registrant in the successful defense of any
     action, suit or proceeding) is asserted by such director, officer or
     controlling person in connection with the securities being registered, the
     Registrant will, unless in the opinion of its counsel the matter has been
     settled by controlling precedent, submit to a court of appropriate
     jurisdiction the question whether such indemnification by it is against
     public policy as expressed in the Securities Act and will be governed by
     the final adjudication of such issue.

                                      II-3

<PAGE>

(i)  The undersigned Registrant hereby undertakes that:

     (1)  For purposes of determining any liability under the Securities Act of
          1933, the information omitted from the form of prospectus filed as
          part of this registration statement in reliance upon Rule 430A and
          contained in a form of prospectus filed by the registrant pursuant to
          Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall be
          deemed to be part of this registration statement as of the time it was
          declared effective.

     (2)  For the purposes of determining any liability under the Securities Act
          of 1933, each post-effective amendment that contains a form of
          prospectus shall be deemed to be a new registration statement relating
          to the securities offered therein, and the offering of such securities
          at that time shall be deemed to be the initial bona fide offering
          thereof.


                                      II-4

<PAGE>



                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Miami, Florida, on the 6th day of September, 2001.

                                     APHTON CORPORATION


                                     By: /S/ PHILIP C. GEVAS
                                        ----------------------------------------
                                        Philip C. Gevas
                                        Chairman, President and Chief Executive
                                        Officer



                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, each person whose signature appears
below constitutes and appoints Philip C. Gevas and Frederick W. Jacobs as his
true and lawful attorneys-in-fact, each acting alone, with full power of
substitution and resubstitution, for such person and in his name, place and
stead in any and all capacities, to sign any or all amendments (including
post-effective amendments) to this Registration Statement, and to file the same,
with exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact full
power and authority to do and perform each and every act and thing requisite and
necessary to be done in and about the premises, as fully for all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that each of said attorneys-in-fact, or their substitute or substitutes, may do
or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>

                Signature                                  Title                              Date
                ---------                                  -----                              ----
<S>                                        <C>                                         <C>

 /S/ PHILIP C. GEVAS                       Chairman, President and Chief               September 6, 2001
--------------------------------------     Executive Officer
Philip C. Gevas

 /S/ ROBERT S. BASSO                       Director                                    September 6, 2001
--------------------------------------
Robert S. Basso

                                      II-5

<PAGE>

 /S/ WILLIAM A. HASLER                     Vice Chairman of the Board, Director        September 6, 2001
--------------------------------------     and Co-Chief Executive Officer
William A. Hasler

 /S/ NICHOLAS JOHN STATHIS                 Director                                    September 6, 2001
--------------------------------------
Nicholas John Stathis

                                           Director                                    September 6, 2001
--------------------------------------
Georges Hibon

 /S/ FREDERICK W. JACOBS                   Vice President, Treasurer and Chief         September 6, 2001
--------------------------------------     Accounting Officer
Frederick W. Jacobs

</TABLE>
                                      II-6

<PAGE>


                                  EXHIBIT INDEX




 Exhibit No.    Description

    4.1        Certificate of Incorporation of Aphton Corporation (Incorporated
               by reference to Exhibit 3.1 to the registrant's Current Report on
               Form 8-K filed on January 30, 1998).

    4.2        Specimen of Common Stock Certificate (Incorporated by reference
               to Exhibit 4.1 to the Company's Registration Statement on Form
               8-A filed on January 30, 1998).

    4.3        Form of Stock Purchase Agreement, dated August 27, 2001.

    5.1        Opinion of White & Case LLP.

   23.1        Consent of Ernst & Young LLP.

   23.2        Consent of PricewaterhouseCoopers LLP.

   23.3        Consent of White & Case LLP (included in their opinion
               filed as Exhibit 5.1 hereto).

   24.1        Power of Attorney (included on signature pages of this
               Registration Statement).