As filed with the Securities and Exchange Commission on December 19, 2001
                                                              File No. 333-72964

================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                              ---------------------
                                 Amendment No. 1
                                       to
                                    FORM S-3
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933
                             ----------------------

                               APHTON CORPORATION
             (Exact name of registrant as specified in its charter)

     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
               (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. |_|

                             ----------------------
     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 DECEMBER 19, 2001

                                   PROSPECTUS

                                1,500,000 Shares

                               APHTON CORPORATION

                                  Common Stock

     This prospectus allows us to issue and sell, from time to time in one or
more offerings, up to 1,500,000 shares of our common stock. On December _, 2001,
we entered into a distribution agreement with UBS Warburg LLC ("UBS"), pursuant
to which we may sell them shares of our common stock from time to time as
described in the section entitled "Plan of Distribution."

     o    We will provide a prospectus supplement each time we issue shares of
          our common stock.

     o    The prospectus supplement will inform you about the specific terms of
          the offering and also may add, update or change information contained
          in this document.

     o    You should read this document and any prospectus supplement carefully
          before you invest.

     Our common stock is traded on the Nasdaq National Market under the symbol
"APHT." On December 18, 2001, the last reported sale price for our common stock
on the Nasdaq National Market was $14.97 per share.

     Investing in our common stock involves risks. See "Risk Factors" beginning
on page 3 of this prospectus for a discussion of certain factors you should
consider before you buy shares of our common stock.

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

     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


PROSPECTUS SUMMARY.............................................................1

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

THE OFFERING...................................................................3

RISK FACTORS...................................................................3

NOTICE TO INVESTORS...........................................................10

FORWARD-LOOKING STATEMENTS....................................................11

USE OF PROCEEDS...............................................................12

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

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

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

WHERE YOU CAN FIND MORE INFORMATION...........................................14

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

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


<PAGE>


     This prospectus does not contain all of the information included in the
registration statement and the exhibits to the registration statement.
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. 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, 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 also are developing products to neutralize
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).

     We have financed our operations since inception through the sale of our
equity securities and, to a lesser extent, using 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 finance technology and product
development, manufacturing and clinical trials.

     Currently, we are conducting an end-stage Phase III clinical trial with
patients with advanced pancreatic cancer in the U.S. and in Europe. We are
conducting additional advanced-stage trials with our anti-gastrin vaccine, which
contains antibodies to neutralize gastrin 17 (a hormone that is released after
eating and is linked in certain cases to the growth of cancer), for patients
with colorectal cancer who are no longer responding to chemotherapy and for
patients diagnosed with advanced stomach cancer. A fourth trial is underway in
the U.S. and Europe using our GnRH pharmaccine, which is a therapeutic vaccine
for the treatment of chronic diseases and cancer, for prostate cancer patients
who are no longer responding to hormone therapy.

     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 into the first quarter of the year 2002. Our
working capital and capital requirements will depend on numerous factors,
including the following:

     o    the progress of our research and development program, preclinical
          testing and clinical trials;

     o    the timing and cost of obtaining regulatory approvals;


<PAGE>


     o    the levels of resources that we devote to product development,
          manufacturing and marketing capabilities;

     o    technological advances;

     o    competition; and

     o    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.



                                      -2-
<PAGE>


                                  THE OFFERING


     Common stock offered by this prospectus..............1,500,000 shares

     Common stock outstanding after the offering..........18,886,996 shares (1)

     Use of proceeds......................................For general corporate
                                                          purposes, including
                                                          our ongoing clinical
                                                          trials and operations.

     Nasdaq National Market symbol .......................APHT

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

(1)  Assumes the sale of all of the shares offered hereby. Based on shares
     outstanding as of December 14, 2001. Does not include:

     -    2,700,000 shares of common stock issuable upon exercise of outstanding
          warrants as of December 14, 2001, or

     -    shares which may be issued pursuant to the anti-dilution rights of the
          holders of 1,187,503 shares of our common stock issued in connection
          with a private placement on August 24, 2001.



                                  RISK FACTORS


     If you purchase shares of our common stock, you will take on a financial
risk. In deciding whether to invest, you should consider carefully 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 do not consider material also may 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 to treat pancreatic cancer, is in end stage trials in the United
States and Europe. Our other current potential products to treat 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.
These potential products may not be developed successfully into immunogens that
can be administered to humans or may not prove to be safe and effective in
clinical trials or cost-


                                      -3-
<PAGE>


effective to manufacture and administer. We may encounter problems in clinical
trials that will cause us to delay or suspend a clinical trial. Also, our
products that are currently under development may not be completed successfully
or within an acceptable time period, if at all. The testing may not show the
products to be safe or effective. Further, our products may not receive
regulatory approval. Finally, if any of our products do receive required
regulatory approval, we may not be capable of producing those products in
commercial quantities at reasonable costs or those products may not be accepted
by the marketplace.

     We expect to continue incurring substantial operating losses in the next
several years. We have experienced significant operating losses since our
inception in 1981 and expect to continue incurring 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 September 30, 2001, we had an accumulated deficit of approximately $87.4
million. Our ability to achieve profitability depends upon our ability, alone or
through relationships with third parties, to develop successfully our technology
and products, to obtain required regulatory approvals and to manufacture, market
and sell such products.

     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. Developing 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:

     o    continued scientific progress in the research and development
          (clinical trials) of our products,

     o    our ability to collaborate with others for the manufacture, marketing
          and sale of our products,

     o    the cost of regulatory approvals,

     o    the cost of establishing, maintaining and enforcing intellectual
          property rights, competing technological and market developments, and

     o    changes in our existing research relationships.

     Our net rate of expenditure during the eight months ended September 30,
2001 averaged approximately $2.3 million per month. We anticipate, however, that
our rate of expenditure will increase as we proceed through the Phase III
clinical trials for our anti-gastrin immunogen products. Our 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 first
quarter of the year 2002.


                                      -4-
<PAGE>


     We may seek additional financing through collaborative arrangements or
through public or private equity or debt financings. Additional financing may
not be available to us 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. Our approach may ultimately prove to be
unsuccessful since:

     o    we may not successfully complete our product development efforts,

     o    our products may not be proven to be safe and effective,

     o    we may not receive approval from the U.S. Food and Drug
          Administration, or FDA, or any other applicable regulatory agency, or

     o    medical centers, hospitals, physicians or patients may not 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.

     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 undergo rigorous testing and approval
processes by the FDA and equivalent foreign regulatory authorities, including
the Medicines Control Agency, or 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 to
treat 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


                                      -5-
<PAGE>


be required prior to marketing such a product in the United States. Although we
have filed an Investigational New Drug application, or 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. 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. Approval for any products we develop
may not be granted by applicable regulatory agencies on a timely basis, if at
all, or if granted the approval may not cover all the clinical indications for
which we are seeking approval or may 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, necessary 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 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. Our
competitors may 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.

     As of December 14, 2001 we held 24 issued patents and have pending patent
applications and patent applications in preparation. Our pending applications or
patent applications in preparation or may not be issued as patents in the
future. Additionally, our existing patents, patents pending and patents that we
may subsequently obtain will not necessarily preclude competitors from
developing products that compete with products we have developed and thus would
substantially lessen the value of our proprietary rights. We intend to file
additional patent


                                      -6-
<PAGE>


applications, when appropriate, relating to our technologies, improvements to
our technologies and specific products we may develop. If any of our patents are
challenged, invalidated, circumvented 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 may be required to obtain licenses to patents,
patent applications or other proprietary rights of others. 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. Our products may
ultimately be found to infringe on the patents or proprietary rights of others.
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 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. We protect
our proprietary technology and processes, in part, by confidentiality agreements
with our employees, consultants and certain contractors. These agreements may
not ultimately provide us with adequate protection.

     We depend on key personnel. We depend upon the services of our senior
management, none of whom is 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
we may not be able to attract or retain such individuals.

     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 if 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. Insurance coverage may not 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.


                                      -7-
<PAGE>


     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.

     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 perform successfully
their contractual responsibilities, the amount and timing of resources to be
dedicated to these activities will not be within our control. Such parties may
not perform their obligations as expected, we may not derive any revenues from
such arrangements and our reliance on others for manufacturing products may
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.

     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 health care
reform proposals or legislation. Further, to the extent that such proposals or
reforms have an adverse effect on our business, financial condition and
profitability or that of other biotechnology or pharmaceutical companies that
are prospective corporate partners for certain of our products, our ability to
commercialize our products may be affected adversely.


                                      -8-
<PAGE>


     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. Any product that we succeed in bringing to market may not
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.

     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

     o    scientific discoveries,

     o    strategic partnerships or arrangements,

     o    technological innovations,

     o    litigation,

     o    commercial products,

     o    patents or proprietary rights,

     o    the progress of clinical trials,

     o    government regulation,

     o    public concern as to the safety of drugs and reliability of our
          testing processes,

     o    general market conditions may have a significant effect on the market
          price of our common stock, and

     o    fluctuations in financial performance from period to period may have a
          significant impact on the market price of our common stock.

     The exercise of outstanding warrants and other rights to obtain additional
shares could dilute the value of the shares. As of December 14, 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. Because of existing
antidilution rights, issuances under the distribution agreement with UBS Warburg
LLC which are made at a price per share of less than $12.00 may result in the
issuance of a significant number of


                                      -9-
<PAGE>


additional shares. We have granted antidilution rights to the holders of
1,187,503 shares of our common stock whereby in the event that, at any time
before September 21, 2002, 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, then
we must issue to those holders 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 price paid by those holders) by that lesser
purchase price minus (b) 1,187,503 (the total number of shares purchased by
those holders). For example, if we issue shares of common stock at a price of
$10.00 per share during the period ended September 21, 2002, then we must issue
an aggregate of 237,500 shares of common stock to those holders. 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. 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.

                               NOTICE TO INVESTORS

     We have not authorized any dealer, salesperson or other person to give any
information or to make any representation other than those contained or
incorporated by reference in this prospectus and any accompanying prospectus
supplement. You must not rely upon any information or representation not
contained or incorporated by reference in this prospectus or any accompanying
prospectus supplement as if we had authorized it.

     This prospectus and any accompanying prospectus supplement do not
constitute an offer to sell or the solicitation of an offer to buy any
securities other than the registered securities to which they relate, nor does
this prospectus and any accompanying prospectus supplement constitute an offer
to sell or the solicitation of an offer to buy any securities in any
jurisdiction to any person to whom it is unlawful to make such offer or
solicitation in such jurisdiction.

     You should not assume that the information contained in this prospectus and
any accompanying prospectus supplement is correct on any date after their
respective dates, even though this prospectus or any prospectus supplement is
delivered or securities are sold on a later date.

     Certain persons participating in an offering may engage in transactions
that stabilize, maintain or otherwise affect the price of the common stock,
including over-allotment, stabilizing and short-covering transactions in such
common stock, and the imposition of a penalty bid,


                                      -10-
<PAGE>


and bidding for and purchasing shares of the common stock in the open market
during and after an offering.


                           FORWARD-LOOKING STATEMENTS


     This prospectus, any prospectus supplement and the documents incorporated
by reference in this prospectus may contain forward-looking statements. 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 cannot guarantee that we will receive any proceeds in connection with
this offering. We will receive the proceeds from any sale of shares to or
through UBS Warburg LLC as described in the Plan of Distribution but we will
receive no proceeds from any subsequent sale of these shares by UBS Warburg LLC.


                                      -11-
<PAGE>


     We plan to use the net proceeds from the sale of our common stock for
general corporate purposes, including to fund our ongoing clinical trials and
operations. Currently, we are conducting an end-stage Phase III clinical trial
with patients with advanced pancreatic cancer in the U.S. and in Europe. We are
conducting additional advanced-stage trials with our anti-gastrin vaccine, which
contains antibodies to neutralize gastrin 17 (a hormone that is released after
eating and is linked in certain cases to the growth of cancer), for patients
with colorectal cancer who are no longer responding to chemotherapy and for
patients diagnosed with advanced stomach cancer. A fourth trial is underway in
the U.S. and Europe using our GnRH pharmaccine, which is a therapeutic vaccine
for the treatment of chronic diseases and cancer, for prostate cancer patients
who are no longer responding to hormone therapy. We have not identified
precisely the amounts we plan to spend on each of these areas or the timing of
such expenditures. Accordingly, our management will have significant flexibility
in applying such proceeds.

     We will require additional funds in the 12-month period following this
offering to continue to fund our ongoing clinical trials and operations.
Additional capital may be raised through additional public or private equity
financing, as well as collaborative relationships, borrowings and other
available sources.

                              PLAN OF DISTRIBUTION

We may offer our common stock directly to purchasers, to or through
underwriters, through dealers or agents, or through a combination of such
methods, which may include sales to or through UBS pursuant to a distribution
agreement dated December __, 2001, between Aphton Corporation and UBS, as
principal or agent, as the case may be . Pursuant to the terms of the
distribution agreement, we have agreed to sell, and UBS has agreed to use its
best efforts to solicit offers to purchase blocks on an agency basis and/or to
purchase on a principal basis, up to a total of 1,500,000 shares of common stock
from time to time during the period ending January 21, 2002 or until April 20,
2002 if extended by UBS and agreed to by us. A "block," as more fully defined in
Rule 10b-18 promulgated under the Exchange Act, is the lesser of (i) at least
2,000 shares totaling 150% or more of the average daily trading volume of our
common stock over the prior four weeks; (ii) at least 5,000 shares purchased for
at least $50,000; or (iii) any number of shares purchased for at least $200,000.
Such blocks do not include amounts purchased by a broker or dealer for the
purpose of sale or resale to us or any affiliate of ours, nor amounts sold short
to us or any affiliate of ours, if we or our affiliate know or have reason to
know that such a purchase or short sale was made.


     If we make sales pursuant to the distribution agreement, on any trading day
during the term of the distribution agreement, we may elect, by giving UBS a
purchase notice to that effect, to issue and sell to UBS, as agent or as
principal, a number of shares of common stock that is not less than 5% and not
more than 20% of the average trading volume of our common stock on the Nasdaq
National Market for the previous thirty days.

     We also may give UBS an option to elect to purchase, as principal, up to
twice the number of shares specified in our purchase notice, except that if the
number to be purchased


                                      -12-
<PAGE>


exceeds 50% of the total number of shares of our common stock traded on such
trading day, such number shall be reduced to 50% unless UBS waives this
condition.

     The purchase price of the shares we sell to UBS as principal will be the
volume weighted average price for that trading day less an underwriting discount
of 6% (or 5.25% if UBS exercises its option to increase the number of shares
specified in our purchase notice).

     The purchase price of the blocks we sell to UBS as principal shall be
mutually agreed on that trading day. The purchase price of the blocks solicited
for sale by UBS as agent will be negotiated between UBS and us.

     Any additional terms of sales to or through UBS pursuant to the
distribution agreement will be set out in more detail in a prospectus supplement
to this prospectus.

     The common stock sold under the distribution agreement will be sold at
prices related to the prevailing market price for such securities, and therefore
exact figures regarding proceeds which will be raised or commissions to be paid
are impossible to determine and will be described in a prospectus supplement to
this prospectus.

     If underwriters, other than UBS, are used in an offering of our common
stock, we will execute an underwriting agreement with such underwriters and will
set out the name of each underwriter and the terms of the transaction, including
any underwriting discounts and other terms constituting compensation of the
underwriters and any dealers in a post effective amendment to the registration
statement. If an underwriting syndicate is used, the managing underwriter(s)
will be set forth on the cover of a prospectus supplement. Common stock will be
acquired by the underwriters for their own accounts and may be resold from time
to time in one or more transactions, including negotiated transactions, at a
fixed public offering price or at varying prices determined at the time of sale.
Any public offering price and any discounts or concessions allowed or reallowed
or paid to dealers may be changed from time to time.

     If dealers are used in an offering of our common stock, we will sell the
common stock to the dealers as principals. The dealers then may resell such
shares of common stock to the public at varying prices which they determine at
the time of resale. The names of the dealers and the terms of the transaction
will be set forth in a prospectus supplement.

     If agents are used in an offering of our common stock, the names of the
agents and the terms of the agency will be set forth in a prospectus supplement.
Unless otherwise indicated in a prospectus supplement, the agents will act on a
best-efforts basis for the period of their appointment.

     Dealers and agents named in a prospectus supplement are deemed to be
underwriters (within the meaning of the Securities Act of 1933) of the
Securities described therein. Underwriters, dealers and agents, may be entitled
to indemnification by us against certain liabilities (including liabilities
under the Securities Act of 1933) under underwriting or other agreements. The
terms of any indemnification provisions will be set forth in a prospectus
supplement.


                                      -13-
<PAGE>


     We also may solicit offers to purchase our common stock from, and sell
common stock directly to, institutional investors or others who may be deemed to
be underwriters within the meaning of the Securities Act of 1933 with respect to
any resales thereof. The terms of any offer will be set forth in a prospectus
supplement.

     Certain underwriters, dealers or agents and their associates may engage in
transactions with, and perform services for us in the ordinary course of
business and receive customary fees for such services. UBS acted as our agent in
connection with a private placement of our common stock in August 2001.

     If so indicated in a prospectus supplement, we will authorize underwriters
or other persons acting as our agents to solicit offers by institutional
investors to purchase our common stock pursuant to contracts providing for
payment and delivery on a future date. The obligations of any institutional
investor will be subject to the condition that its purchase of our common stock
will not be illegal, at the time of delivery. The underwriters and other agents
will not be responsible for the validity or performance of contracts.

     To facilitate an offering of our common stock, certain persons
participating in the offering may engage in transactions that stabilize,
maintain or otherwise affect the price of our common stock. This may include
over-allotments of the common stock. Over-allotments involve the sale by persons
participating in the offering of more common stock than we have sold to them. In
such circumstances, these persons would cover over-allotments by purchasing our
common stock in the open market or by exercising their over-allotment options.
In addition, such persons may stabilize or maintain the price of our common
stock by bidding for or purchasing our common stock in the open market or by
imposing penalty bids, whereby selling concessions allowed to dealers
participating in any such offering may be reclaimed if common stock they sell
are repurchased in connection with stabilization transactions. The effect of
these transactions may be to stabilize or maintain the market price of our
common stock at a level above that which might otherwise prevail in the open
market. These transactions, if commenced, may discontinue at any time.


                                  LEGAL MATTERS


     Certain legal matters with respect to the shares of our common stock
offered pursuant to this registration statement will be passed upon by White &
Case LLP, New York, New York. Certain legal matters will be passed upon for any
agents or underwriters by Stroock & Stroock & Lavan 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.


                                      -14-
<PAGE>


     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.


                       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 Reports on Form 10-Q for the two and five months ended June
          30, 2001, and for the three and eight months ended September 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:


                                      -15-
<PAGE>


                               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.


                                      -16-
<PAGE>


                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.*

         SEC registration fee....................................$         5,149
         Legal fees and expenses.................................$       150,000
         Accounting fees and expenses............................$        12,000
         Miscellaneous...........................................$         1,851
                                                                  --------------
                  Total..........................................$       169,000
                                                                  ==============

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


                                      -1-
<PAGE>


Item 16. Exhibits.


        Exhibit No.                              Description
        -----------                              -----------

           1.1                         Form of Distribution Agreement.
           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).
           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.

----------------
* Previously filed.



                                      -2-
<PAGE>


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 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


                                      -3-
<PAGE>


     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.

(c)  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.

(d)  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.


                                      -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 19thday of December 2001.

                                      APHTON CORPORATION


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


     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>
                                           Chairman of the Board,                           December 19, 2001
              *                            President and Chief Executive Officer
--------------------------------------
Philip C. Gevas

              *                            Director                                         December 19, 2001
--------------------------------------
Robert S. Basso

              *                            Vice Chairman of the Board, Director             December 19, 2001
--------------------------------------     and Co-Chief Executive Officer
William A. Hasler

              *                            Director                                         December 19, 2001
--------------------------------------
Nicholas John Stathis

                                           Director                                         December 19, 2001
-------------------------------------
Georges Hibon

              *                            Vice President, Treasurer, Chief                 December 19, 2001
--------------------------------------     Accounting Officer and Principal
Frederick W. Jacobs                        Financial Officer

</TABLE>


                                      -5-
<PAGE>


*By:  /S/ PHILIP C. GEVAS..
     -----------------------------------
     Philip C. Gevas
    Attorney-in-fact


                                      -6-
<PAGE>


                                  EXHIBIT INDEX


            Exhibit No.                Description
            -----------                -----------

               1.1                     Form of Distribution Agreement.

               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).

               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.

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

* Previously filed.