NEITHER THESE  SECURITIES  NOR THE  SECURITIES  INTO WHICH THESE  SECURITIES ARE
EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE  COMMISSION OR
THE  SECURITIES  COMMISSION  OF ANY STATE IN  RELIANCE  UPON AN  EXEMPTION  FROM
REGISTRATION  UNDER THE  SECURITIES  ACT OF 1933,  AS AMENDED  (THE  "SECURITIES
ACT"),  AND,  ACCORDINGLY,  MAY NOT BE OFFERED  OR SOLD  EXCEPT  PURSUANT  TO AN
EFFECTIVE  REGISTRATION  STATEMENT  UNDER THE  SECURITIES  ACT OR PURSUANT TO AN
AVAILABLE  EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE  REGISTRATION
REQUIREMENTS  OF THE  SECURITIES  ACT AND IN ACCORDANCE  WITH  APPLICABLE  STATE
SECURITIES  LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO
SUCH  EFFECT,  THE  SUBSTANCE  OF WHICH SHALL BE  REASONABLY  ACCEPTABLE  TO THE
COMPANY.  THESE  SECURITIES AND THE  SECURITIES  ISSUABLE UPON EXERCISE OF THESE
SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER
LOAN SECURED BY SUCH SECURITIES.

                               APHTON CORPORATION


                                     WARRANT


Warrant No. 1                       Date of Original Issuance: February 24, 2003

     Aphton  Corporation,   a  Delaware  corporation  (the  "Company"),   hereby
certifies that, for value received, Mainfield Enterprises Inc. or its registered
assigns (the  "Holder"),  is entitled to purchase from the Company up to a total
of 150,000 shares of common stock, $0.001 par value (the "Common Stock"), of the
Company (each such share,  a "Warrant  Share" and all such shares,  the "Warrant
Shares") at an exercise price equal to $2.96 per share (as adjusted from time to
time as provided in Section 9, the "Exercise Price"),  at any time and from time
to time from and after the date hereof and through and  including  February  24,
2008 (the "Expiration Date"), and subject to the following terms and conditions:

     1. Definitions. In addition to the terms defined elsewhere in this Warrant,
capitalized  terms that are not otherwise defined herein shall have the meanings
given to such terms in the Securities  Purchase  Agreement of even date herewith
to which  the  Company  and the  original  Holder  are  parties  (the  "Purchase
Agreement").

     2. Registration of Warrant.  The Company shall register this Warrant,  upon
records  to be  maintained  by  the  Company  for  that  purpose  (the  "Warrant
Register"),  in the name of the  record  Holder  hereof  from time to time.  The
Company may deem and treat the registered Holder of this Warrant as the absolute
owner hereof for the purpose of any exercise  hereof or any  distribution to the
Holder, and for all other purposes, absent actual notice to the contrary.
<PAGE>


     3.  Registration  of Transfers.  The Company shall register the transfer of
any portion of this  Warrant in the Warrant  Register,  upon  surrender  of this
Warrant,  with the Form of Assignment attached hereto duly completed and signed,
to the Company at its address  specified  herein.  Upon any such registration or
transfer,  a new Warrant to purchase Common Stock, in substantially  the form of
this Warrant (any such new Warrant, a "New Warrant"),  evidencing the portion of
this Warrant so transferred  shall be issued to the transferee and a New Warrant
evidencing  the remaining  portion of this Warrant not so  transferred,  if any,
shall be issued to the transferring Holder. The acceptance of the New Warrant by
the transferee  thereof shall be deemed the acceptance by such transferee of all
of the rights and obligations of a holder of a Warrant.

     4. Exercise and Duration of Warrants.  This Warrant shall be exercisable by
the  registered  Holder  at any time and from  time to time on or after the date
hereof to and including the Expiration Date. At 6:30 p.m., New York City time on
the  Expiration  Date,  the portion of this Warrant not exercised  prior thereto
shall be and become void and of no value,  provided,  that if the closing  sales
price of the Common  Stock on the  Expiration  Date is greater  than 102% of the
Exercise Price on the Expiration Date, then this Warrant shall be deemed to have
been exercised in full (to the extent not  previously  exercised) on a "cashless
exercise" basis at 6:30 P.M. New York City time on the Expiration Date.

     5. Delivery of Warrant Shares.

          (a) To effect conversions hereunder,  the Holder shall not be required
to  physically  surrender  this  Warrant  unless the  aggregate  Warrant  Shares
represented  by this Warrant is being  exercised.  Upon delivery of the Exercise
Notice to the Company  (with the attached  Warrant  Shares  Exercise Log) at its
address  for notice  set forth  herein and upon  payment of the  Exercise  Price
multiplied by the number of Warrant  Shares that the Holder  intends to purchase
hereunder,  the Company shall promptly (but in no event later than three Trading
Days after the Date of Exercise  (as defined  herein))  issue and deliver to the
Holder, a certificate for the Warrant Shares issuable upon such exercise, which,
unless  otherwise  required  by  the  Purchase  Agreement,   shall  be  free  of
restrictive  legends.  The  Company  shall,  upon  request  of  the  Holder  and
subsequent to the date on which a registration  statement covering the resale of
the Warrant  Shares has been declared  effective by the  Securities and Exchange
Commission,   use  its  best  efforts  to  deliver   Warrant  Shares   hereunder
electronically  through the Depository Trust Corporation or another  established
clearing corporation performing similar functions, if available, provided, that,
the Company may,  but will not be required to change its  transfer  agent if its
current transfer agent cannot deliver Warrant Shares electronically  through the
Depository Trust  Corporation.  A "Date of Exercise" means the date on which the
Holder  shall have  delivered  to Company:  (i) the  Exercise  Notice  (with the
Warrant  Exercise Log attached to it),  appropriately  completed and duly signed
and (ii) if such Holder is not utilizing the cashless  exercise  provisions  set
forth in this Warrant,  payment of the Exercise  Price for the number of Warrant
Shares so indicated by the Holder to be purchased.

          (b) If by the third  Trading Day after a Date of Exercise  the Company
fails to deliver the required  number of Warrant  Shares in the manner  required
pursuant to Section  5(a),  then the Holder will have the right to rescind  such
exercise.
<PAGE>

          (c) If by the third  Trading Day after a Date of Exercise  the Company
fails to deliver the required  number of Warrant  Shares in the manner  required
pursuant to Section  5(a),  and if after such third Trading Day and prior to the
receipt  of such  Warrant  Shares,  the  Holder  purchases  (in an  open  market
transaction or otherwise) shares of Common Stock to deliver in satisfaction of a
sale by the Holder of the Warrant Shares which the Holder anticipated  receiving
upon such exercise (a  "Buy-In"),  then the Company shall (1) pay in cash to the
Holder the amount by which (x) the  Holder's  total  purchase  price  (including
brokerage  commissions,  if any) for the  shares  of Common  Stock so  purchased
exceeds (y) the amount  obtained by multiplying (A) the number of Warrant Shares
that the Company was  required to deliver to the Holder in  connection  with the
exercise at issue by (B) the  closing bid price of the Common  Stock at the time
of the obligation giving rise to such purchase  obligation and (2) at the option
of the Holder, either reinstate the portion of the Warrant and equivalent number
of  Warrant  Shares for which such  exercise  was not  honored or deliver to the
Holder the number of shares of Common  Stock that would have been issued had the
Company timely  complied with its exercise and delivery  obligations  hereunder.
The Holder  shall  provide the Company  written  notice  indicating  the amounts
payable to the Holder in respect of the Buy-In.

          (d) The Company's  obligations to issue and deliver  Warrant Shares in
accordance with the terms hereof are absolute and unconditional, irrespective of
any action or inaction by the Holder to enforce the same,  any waiver or consent
with respect to any provision  hereof,  the recovery of any judgment against any
Person  or  any  action  to  enforce  the  same,  or any  setoff,  counterclaim,
recoupment,  limitation or  termination,  or any breach or alleged breach by the
Holder or any other Person of any  obligation to the Company or any violation or
alleged violation of law by the Holder or any other Person,  and irrespective of
any other  circumstance  which  might  otherwise  limit such  obligation  of the
Company to the Holder in connection with the issuance of Warrant Shares. Nothing
herein shall limit a Holder's right to pursue any other remedies available to it
hereunder,  at law or in  equity  including,  without  limitation,  a decree  of
specific  performance  and/or  injunctive  relief with respect to the  Company's
failure to timely deliver certificates  representing shares of Common Stock upon
exercise of the Warrant as required pursuant to the terms hereof.

     6. Charges,  Taxes and Expenses.  Issuance and delivery of certificates for
shares of Common  Stock upon  exercise  of this  Warrant  shall be made  without
charge to the Holder for any issue or transfer tax,  withholding  tax,  transfer
agent fee or other  incidental tax or expense in respect of the issuance of such
certificates,  all of which  taxes and  expenses  shall be paid by the  Company;
provided,  however,  that the Company shall not be required to pay any tax which
may be payable in respect of any transfer  involved in the  registration  of any
certificates  for  Warrant  Shares or  Warrants in a name other than that of the
Holder.  The Holder shall be  responsible  for all other tax liability  that may
arise as a result of holding or transferring  this Warrant or receiving  Warrant
Shares upon exercise hereof.

     7. Replacement of Warrant.  If this Warrant is mutilated,  lost,  stolen or
destroyed,  the  Company  shall  issue or cause to be  issued  in  exchange  and
substitution for and upon  cancellation  hereof,  or in lieu of and substitution
for this Warrant,  a New Warrant,  but only upon receipt of evidence  reasonably
satisfactory to the Company of such loss, theft or destruction and customary and
reasonable  indemnity  (which shall not include a surety  bond),  if  requested.
Applicants  for a New Warrant  under such  circumstances  shall also comply with
such other
<PAGE>


reasonable  regulations and procedures and pay such other reasonable third-party
costs as the Company may prescribe. If a New Warrant is requested as a result of
a  mutilation  of this  Warrant,  then the Holder shall  deliver such  mutilated
Warrant to the Company as a condition  precedent to the Company's  obligation to
issue the New Warrant.

     8. Reservation of Warrant Shares. The Company covenants that it will at all
times  reserve and keep  available out of the  aggregate of its  authorized  but
unissued  and  otherwise  unreserved  Common  Stock,  solely for the  purpose of
enabling  it to issue  Warrant  Shares upon  exercise of this  Warrant as herein
provided,  the number of Warrant Shares which are then issuable and  deliverable
upon the exercise of this entire  Warrant,  free from  preemptive  rights or any
other  contingent  purchase rights of persons other than the Holder (taking into
account the  adjustments and  restrictions of Section 9). The Company  covenants
that all Warrant Shares so issuable and deliverable shall, upon issuance and the
payment of the applicable Exercise Price in accordance with the terms hereof, be
duly and validly authorized, issued and fully paid and nonassessable.

     9. Certain  Adjustments.  The Exercise  Price and number of Warrant  Shares
issuable upon  exercise of this Warrant are subject to  adjustment  from time to
time as set forth in this Section 9.

          (a) Stock Dividends and Splits. If the Company, at any time while this
Warrant  is  outstanding,  (i)  pays a stock  dividend  on its  Common  Stock or
otherwise  makes a distribution on any class of capital stock that is payable in
shares of Common Stock, (ii) subdivides  outstanding shares of Common Stock into
a larger number of shares, or (iii) combines  outstanding shares of Common Stock
into a smaller number of shares, then in each such case the Exercise Price shall
be multiplied by a fraction of which the numerator shall be the number of shares
of Common  Stock  outstanding  immediately  before  such  event and of which the
denominator   shall  be  the  number  of  shares  of  Common  Stock  outstanding
immediately after such event. Any adjustment made pursuant to clause (i) of this
paragraph  shall  become  effective  immediately  after the record  date for the
determination of stockholders entitled to receive such dividend or distribution,
and any  adjustment  pursuant  to clause (ii) or (iii) of this  paragraph  shall
become  effective  immediately  after the effective date of such  subdivision or
combination.  If any event requiring an adjustment  under this paragraph  occurs
during the period  that an  Exercise  Price is  calculated  hereunder,  then the
calculation  of such Exercise Price shall be adjusted  appropriately  to reflect
such event.

          (b) Pro Rata  Distributions.  If the  Company,  at any time while this
Warrant is outstanding, distributes to all holders of Common Stock (i) evidences
of its  indebtedness,  (ii) any security  (other than a  distribution  of Common
Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe
for  or  purchase  any  security,  or  (iv)  any  other  asset  (in  each  case,
"Distributed Property"), then, at the request of any Holder delivered before the
90th day after the record date fixed for determination of stockholders  entitled
to receive such  distribution,  the Company will deliver to such Holder,  within
five Trading Days after such request  (or, if later,  on the  effective  date of
such  distribution),  the Distributed  Property that such Holder would have been
entitled  to receive in respect of the  Warrant  Shares for which such  Holder's
Warrant could have been exercised immediately prior to such record date. If such
Distributed  Property is not  delivered  to a Holder  pursuant to the  preceding
sentence,  then upon any  exercise of the
<PAGE>


Warrant  that occurs  after such record  date,  such Holder shall be entitled to
receive,  in  addition  to the  Warrant  Shares  otherwise  issuable  upon  such
conversion,  the Distributed  Property that such Holder would have been entitled
to receive in respect of such  number of Warrant  Shares had the Holder been the
record holder of such Warrant Shares immediately prior to such record date.

          (c)  Fundamental  Transactions.  If, at any time while this Warrant is
outstanding,  (1) the Company effects any merger or consolidation of the Company
with  or into  another  Person,  (2)  the  Company  effects  any  sale of all or
substantially all of its assets in one or a series of related transactions,  (3)
any tender offer or exchange offer (whether by the Company or another Person) is
completed  pursuant to which  holders of Common Stock are permitted to tender or
exchange their shares for other securities, cash or property, or (4) the Company
effects  any  reclassification  of the  Common  Stock  or any  compulsory  share
exchange  pursuant to which the Common Stock is  effectively  converted  into or
exchanged  for  other  securities,  cash  or  property  (in  any  such  case,  a
"Fundamental  Transaction"),  then the Holder shall have the right thereafter to
receive,  upon exercise of this Warrant, the same amount and kind of securities,
cash or property as it would have been  entitled to receive upon the  occurrence
of such  Fundamental  Transaction  if it had  been,  immediately  prior  to such
Fundamental  Transaction,  the  holder of the  number  of  Warrant  Shares  then
issuable upon exercise in full of this Warrant (the "Alternate  Consideration").
For purposes of any such exercise, the determination of the Exercise Price shall
be appropriately adjusted to apply to such Alternate  Consideration based on the
amount of  Alternate  Consideration  issuable  in respect of one share of Common
Stock in such  Fundamental  Transaction,  and the Company  shall  apportion  the
Exercise  Price  among  the  Alternate  Consideration  in  a  reasonable  manner
reflecting  the relative  value of any  different  components  of the  Alternate
Consideration.  If  holders  of Common  Stock  are  given  any  choice as to the
securities,  cash or property to be received in a Fundamental Transaction,  then
the Holder shall be given the same choice as to the Alternate  Consideration  it
receives  upon  any  exercise  of  this  Warrant   following  such   Fundamental
Transaction. At the Holder's option and request, any successor to the Company or
surviving entity in such Fundamental  Transaction shall, either (1) issue to the
Holder a new warrant  substantially  in the form of this Warrant and  consistent
with the foregoing  provisions and evidencing the Holder's right to purchase the
Alternate  Consideration for the aggregate Exercise Price upon exercise thereof,
or (2)  purchase the Warrant  from the Holder for a purchase  price,  payable in
cash within five Trading Days after such request (or, if later, on the effective
date of the  Fundamental  Transaction),  equal to the Black Scholes value of the
remaining  unexercised portion of this Warrant on the date of such request.  The
terms of any agreement  pursuant to which a Fundamental  Transaction is effected
shall include terms  requiring any such successor or surviving  entity to comply
with the  provisions of this paragraph (c) and insuring that the Warrant (or any
such  replacement  security)  will be  similarly  adjusted  upon any  subsequent
transaction analogous to a Fundamental Transaction.

          (d) Number of Warrant  Shares.  Simultaneously  with any adjustment to
the Exercise Price pursuant to paragraphs (a) or (b) of this Section, the number
of Warrant  Shares that may be purchased  upon exercise of this Warrant shall be
increased  or  decreased  proportionately,  so that  after such  adjustment  the
aggregate  Exercise Price payable  hereunder for the adjusted  number of Warrant
Shares shall be the same as the aggregate  Exercise Price in effect  immediately
prior to such adjustment.
<PAGE>


          (e) Calculations.  All calculations under this Section 9 shall be made
to the nearest cent or the nearest 1/100th of a share, as applicable. The number
of shares of Common Stock outstanding at any given time shall not include shares
owned or held by or for the account of the Company,  and the  disposition of any
such shares shall be considered an issue or sale of Common Stock.

          (f) Notice of  Adjustments.  Upon the  occurrence  of each  adjustment
pursuant to this  Section 9, the Company at its expense  will  promptly  compute
such  adjustment  in  accordance  with the terms of this  Warrant  and prepare a
certificate setting forth such adjustment, including a statement of the adjusted
Exercise Price and adjusted number or type of Warrant Shares or other securities
issuable  upon  exercise  of  this  Warrant  (as  applicable),   describing  the
transactions  giving  rise to such  adjustments  and showing in detail the facts
upon which such  adjustment  is based.  Upon written  request,  the Company will
promptly  deliver  a copy of each  such  certificate  to the  Holder  and to the
Company's Transfer Agent.

          (g) Notice of Corporate Events. If the Company (i) declares a dividend
or any other  distribution  of cash,  securities or other property in respect of
its  Common  Stock,  including  without  limitation  any  granting  of rights or
warrants to subscribe  for or purchase  any capital  stock of the Company or any
Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating
or  solicits  stockholder  approval  for any  Fundamental  Transaction  or (iii)
authorizes the voluntary  dissolution,  liquidation or winding up of the affairs
of the Company, then the Company shall deliver to the Holder a notice describing
the material terms and conditions of such transaction, at least 20 calendar days
prior to the applicable record or effective date on which a Person would need to
hold  Common  Stock in order to  participate  in or vote  with  respect  to such
transaction,  and the Company will take all steps reasonably  necessary in order
to insure that the Holder is given the  practical  opportunity  to exercise this
Warrant prior to such time so as to  participate in or vote with respect to such
transaction;  provided,  however, that the failure to deliver such notice or any
defect therein shall not affect the validity of the corporate action required to
be described in such notice.

     10. Payment of Exercise Price. The Holder may pay the Exercise Price in one
of the following manners:

          (a) Cash Exercise. The Holder may deliver immediately available funds;
or

          (b)  Cashless  Exercise.  In the  event  that  there  is not  then  an
effective registration statement that is then available for the Holder to resell
the Warrant Shares  subject to the exercise at issue,  the Holder may deliver an
Exercise Notice of its election to utilize cashless exercise, in which event the
Company  shall issue to the Holder the number of Warrant  Shares  determined  as
follows:

                  X = Y [(A-B)/A]

         where:

                  X = the number of Warrant Shares to be issued to the Holder.
<PAGE>

                  Y = the number of Warrant Shares with
                  respect to which this Warrant is being
                  exercised.

                  A = the average of the closing prices for
                  the five Trading Days immediately prior to
                  (but not including) the Exercise Date.

                  B = the Exercise Price.

For purposes of Rule 144  promulgated  under the Securities Act, it is intended,
understood  and  acknowledged  that the  Warrant  Shares  issued  in a  cashless
exercise  transaction  shall be deemed to have been acquired by the Holder,  and
the holding period for the Warrant Shares shall be deemed to have commenced,  on
the date this Warrant was originally issued.

     11.  Limitation  on  Exercise.  Notwithstanding  anything  to the  contrary
contained  herein,  the number of shares of Common Stock that may be acquired by
the Holder upon any  exercise of this Warrant (or  otherwise in respect  hereof)
shall be limited to the extent necessary to insure that, following such exercise
(or  other  issuance),   the  total  number  of  shares  of  Common  Stock  then
beneficially owned by such Holder and its Affiliates and any other Persons whose
beneficial  ownership of Common Stock would be aggregated  with the Holder's for
purposes of Section  13(d) of the Exchange  Act,  does not exceed  9.999% of the
total number of issued and  outstanding  shares of Common Stock  (including  for
such purpose the shares of Common Stock issuable upon such  exercise).  For such
purposes,  beneficial  ownership  shall be determined in accordance with Section
13(d) of the Exchange Act and the rules and regulations  promulgated thereunder.
Each delivery of an Exercise Notice  hereunder will constitute a  representation
by the Holder that it has evaluated the  limitation  set forth in this paragraph
and determined  that issuance of the full number of Warrant Shares  requested in
such Exercise Notice is permitted under this paragraph. This provision shall not
restrict  the number of shares of Common  Stock  which a Holder  may  receive or
beneficially  own in  order to  determine  the  amount  of  securities  or other
consideration  that such  Holder  may  receive in the event of a merger or other
business  combination or reclassification  involving the Company as contemplated
in Section 9 of this Warrant.

     12. No Fractional  Shares.  No fractional  shares of Warrant Shares will be
issued  in  connection  with  any  exercise  of  this  Warrant.  In  lieu of any
fractional shares which would, otherwise be issuable, the Company shall pay cash
equal to the product of such  fraction  multiplied  by the closing  price of one
Warrant Share as reported on the Nasdaq National Market on the date of exercise.

     13.  Notices.  Any and all notices or other  communications  or  deliveries
hereunder  (including,  without  limitation,  any Exercise  Notice)  shall be in
writing and shall be deemed given and  effective on the earliest of (i) the date
of  transmission,  if such notice or communication is delivered via facsimile at
the facsimile number specified in this Section prior to 6:30 p.m. (New York City
time)  on  a  Trading  Day,  (ii)  the  next  Trading  Day  after  the  date  of
transmission,  if such notice or communication is delivered via facsimile at the
facsimile number specified in this Section on a day that is not a Trading Day or
later than 6:30 p.m. (New York City time) on any Trading Day,  (iii) the Trading
Day following the date of mailing,  if sent by nationally  recognized  overnight
courier service, or (iv) upon actual receipt by the party to whom
<PAGE>


such notice is required to be given. The addresses for such communications shall
be: (i) if to the  Company,  to Aphton  Corp.,  Facsimile  No. [ ], Attn:  Chief
Financial Officer,  or (ii) if to the Holder, to the address or facsimile number
appearing on the Warrant  Register or such other address or facsimile  number as
the Holder may provide to the Company in accordance with this Section.

     14.  Warrant  Agent.  The Company  shall serve as warrant  agent under this
Warrant.  Upon 30 days'  notice to the  Holder,  the  Company  may appoint a new
warrant agent.  Any corporation  into which the Company or any new warrant agent
may be merged or any corporation  resulting from any  consolidation to which the
Company or any new warrant  agent shall be a party or any  corporation  to which
the  Company  or  any  new  warrant  agent  transfers  substantially  all of its
corporate trust or shareholders  services  business shall be a successor warrant
agent under this Warrant  without any further act.  Any such  successor  warrant
agent shall  promptly  cause  notice of its  succession  as warrant  agent to be
mailed (by first class mail, postage prepaid) to the Holder at the Holder's last
address as shown on the Warrant Register.

     15. Miscellaneous.

          (a) This  Warrant  shall be binding on and inure to the benefit of the
parties  hereto and their  respective  successors  and  assigns.  Subject to the
preceding  sentence,  nothing in this Warrant  shall be construed to give to any
Person  other than the  Company  and the Holder  any legal or  equitable  right,
remedy or cause of action under this  Warrant.  This Warrant may be amended only
in  writing  signed by the  Company  and the  Holder  and their  successors  and
assigns.

          (b) All questions concerning the construction,  validity,  enforcement
and  interpretation  of this  Warrant  shall be  governed by and  construed  and
enforced in accordance with the internal laws of the State of New York,  without
regard to the principles of conflicts of law thereof. Each party agrees that all
legal proceedings concerning the interpretations, enforcement and defense of the
transactions  contemplated  by this  Warrant  (whether  brought  against a party
hereto  or  its  respective  affiliates,   directors,  officers,   shareholders,
employees or agents) shall be commenced in the state and federal  courts sitting
in the  City of New  York,  Borough  of  Manhattan.  Each  party  hereto  hereby
irrevocably  submits  to the  exclusive  jurisdiction  of the state and  federal
courts  sitting  in  the  City  of  New  York,  Borough  of  Manhattan  for  the
adjudication  of any dispute  hereunder  or in  connection  herewith or with any
transaction  contemplated  hereby or discussed herein (including with respect to
the enforcement of this Warrant),  and hereby irrevocably waives, and agrees not
to assert in any suit, action or proceeding, any claim that it is not personally
subject  to the  jurisdiction  of any such  court,  that  such  suit,  action or
proceeding is improper.  Each party hereto hereby  irrevocably  waives  personal
service of process and consents to process being served in any such suit, action
or  proceeding  by mailing a copy thereof via  registered  or certified  mail or
overnight  delivery  (with evidence of delivery) to such party at the address in
effect for notices to it under this Warrant and agrees that such  service  shall
constitute good and sufficient  service of process and notice  thereof.  Nothing
contained  herein shall be deemed to limit in any way any right to serve process
in any manner  permitted by law. Each party hereto  (including  its  affiliates,
agents,  officers,  directors and employees) hereby  irrevocably  waives, to the
fullest extent  permitted by applicable  law, any and all right to trial by jury
in any legal  proceeding  arising  out of or  relating  to this  Warrant  or
<PAGE>


the transactions  contemplated  hereby. If either party shall commence an action
or proceeding to enforce any  provisions  of this Warrant,  then the  prevailing
party in such action or  proceeding  shall be  reimbursed by the other party for
its attorneys fees and other costs and expenses incurred with the investigation,
preparation and prosecution of such action or proceeding.

          (c) The headings herein are for convenience  only, do not constitute a
part of this  Warrant  and shall  not be  deemed  to limit or affect  any of the
provisions hereof.

          (d) In case any one or more of the provisions of this Warrant shall be
invalid or unenforceable in any respect,  the validity and enforceability of the
remaining  terms and provisions of this Warrant shall not in any way be affected
or impaired  thereby and the parties  will attempt in good faith to agree upon a
valid  and  enforceable  provision  which  shall  be a  commercially  reasonable
substitute  therefor,  and upon so agreeing,  shall  incorporate such substitute
provision in this Warrant.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                             SIGNATURE PAGE FOLLOWS]
<PAGE>


     IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed
by its authorized officer as of the date first indicated above.


                                      APHTON CORPORATION



                                      By:  /s/ Philip C. Gevas
                                         --------------------------------------
                                         Name:  Philip C. Gevas
                                         Title:  Chief Executive Officer
<PAGE>




                                 EXERCISE NOTICE


To Aphton Corporation:

          The undersigned hereby  irrevocably  elects to purchase  _____________
shares of common  stock,  $0.001  par value  per  share,  of Aphton  Corporation
("Common Stock"),  pursuant to Warrant No. 1, original issued February [ ], 2003
(the  "Warrant"),  and, if such Holder is not  utilizing  the cashless  exercise
provisions  set  forth in the  Warrant,  encloses  herewith  $________  in cash,
certified or official bank check or checks or other immediately available funds,
which sum  represents  the aggregate  Exercise Price (as defined in the Warrant)
for the number of shares of Common Stock to which this Exercise  Notice relates,
together with any applicable  taxes payable by the  undersigned  pursuant to the
Warrant.

          By its delivery of this Exercise  Notice,  the undersigned  represents
and  warrants to the Company  that in giving  effect to the  exercise  evidenced
hereby the Holder will not beneficially own in excess of the number of shares of
Common Stock  (determined  in accordance  with Section  13(d) of the  Securities
Exchange Act of 1934)  permitted to be owned under Section 11 of this Warrant to
which this notice relates.

          The undersigned  requests that  certificates  for the shares of Common
Stock issuable upon this exercise be issued in the name of


                                               PLEASE INSERT SOCIAL SECURITY OR
                                               TAX IDENTIFICATION NUMBER


                         (Please print name and address)
<PAGE>


                           Warrant Shares Exercise Log
                           ---------------------------

                                                              Number of Warrant
Date     Number of Warrant Shares       Number of Warrant    Shares Remaining to
         Available to be Exercised      Shares Exercised        be Exercised
--------------------------------------------------------------------------------
<PAGE>


                               FORM OF ASSIGNMENT


         [To be completed and signed only upon transfer of Warrant]

     FOR VALUE  RECEIVED,  the undersigned  hereby sells,  assigns and transfers
unto  ________________________________  the  right  represented  by  the  within
Warrant to purchase ____________ shares of Common Stock of Aphton Corporation to
which the within  Warrant  relates  and  appoints  ________________  attorney to
transfer  said  right on the books of  Aphton  Corporation  with  full  power of
substitution in the premises.

Dated:   _______________, ____


                                         ---------------------------------------
                                         (Signature must conform in all respects
                                          to name of holder as specified on the
                                          face of the Warrant)



                                         ---------------------------------------
                                         Address of Transferee



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

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


In the presence of:


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