Exhibit 4.2

         THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
          ACT OF 1933 OR ANY APPLICABLE STATE SECURITIES LAWS. THEY MAY
            NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED OR
             OTHERWISE TRANSFERRED IN THE ABSENCE OF A REGISTRATION
          STATEMENT IN EFFECT WITH RESPECT TO THE SECURITIES UNDER SUCH
          ACT OR AN EXEMPTION THEREFROM. ANY SUCH TRANSFER MAY ALSO BE
                  SUBJECT TO APPLICABLE STATE SECURITIES LAWS.



                                  PROCEPT, INC.

                    New Warrant for the Purchase of Shares of
                    -----------------------------------------
                                  Common Stock
                                  ------------


No. N-1                                                        1,149,096 Shares


         FOR VALUE RECEIVED, PROCEPT, INC., a Delaware corporation (the
"Company"), hereby certifies that the Aries Domestic Fund, L.P. or its
registered assigns (the "Holder") is entitled to purchase from the Company,
subject to the provisions of this Warrant (the "Warrant"), at any time
commencing upon the date hereof (the "Initial Exercise Date"), and prior to 5:00
P.M., New York City time, on the date which is five (5) years from the date
hereof (the "Termination Date"), June 30, 2002 fully paid and non-assessable
shares of the Common Stock, $.01 par value, of the Company ("Common Stock"), at
an exercise price of $1.09375 per share of Common Stock for an aggregate
exercise price of One Million Two-Hundred Fifty-Six Thousand Eight Hundred
Twenty-Three Dollars and Seventy-Five Cents ($1,256,823.75) (the aggregate
purchase price payable for the Warrant Shares hereunder is hereinafter sometimes
referred to as the "Aggregate Exercise Price"). The number of shares of Common
Stock to be received upon exercise of this Warrant and the price to be paid for
each share of Common Stock are subject to possible adjustment from time to time
as hereinafter set forth. The shares of Common Stock or other securities or
property deliverable upon such exercise as adjusted from time to time is
hereinafter sometimes referred to as the "Warrant Shares." The exercise price of
a share of Common Stock in effect at any time and as adjusted from time to time
is hereinafter sometimes referred to as the "Per Share Exercise Price." The Per
Share Exercise Price is subject to adjustment as hereinafter provided; in the
event of any such adjustment, the number of Warrant Shares shall be adjusted by
dividing the Aggregate Exercise Price by the Per Share Exercise Price in effect
immediately after such adjustment. The Aggregate Exercise Price is not subject
to adjustment.

         This Warrant was issued in exchange for Class A and Class B Warrants
issued to the original holder hereof on June 30, 1997.



<PAGE>



         1. Exercise of Warrant.

         (a) This Warrant may be exercised in whole or in part, at any time by
the Holder commencing on the Initial Exercise Date and prior to the Termination
Date, by presentation and surrender of this Warrant, together with the duly
executed subscription form attached at the end hereof, at the address set forth
in subsection 8(a) hereof, together with payment, by certified or official bank
check or wire transfer payable to the order of the Company, of the Aggregate
Exercise Price or the proportionate part thereof if exercised in part.

         (b) If this Warrant is exercised in part only, the Company shall, upon
presentation of this Warrant upon such exercise, execute and deliver (along with
the certificate for the Warrant Shares purchased) a new Warrant evidencing the
rights of the Holder hereof to purchase the balance of the Warrant Shares
purchasable hereunder upon the same terms and conditions as herein set forth.
Upon proper exercise of this Warrant, the Company promptly shall deliver
certificates for the Warrant Shares to the Holder duly legended as authorized by
the subscription form. No fractional shares or scrip representing fractional
shares shall be issued upon exercise of this Warrant; provided that the Company
shall pay to the holders of the Warrant cash in lieu of such fractional shares.

         2. Reservation of Warrant Shares; Fully Paid Shares; Taxes. The Company
hereby represents that it has, and until expiration of this Warrant agrees that
it shall, reserve for issuance or delivery upon exercise of this Warrant, such
number of shares of the Common Stock as shall be required for issuance and/or
delivery upon exercise of this Warrant in full, and agrees that all Warrant
Shares so issued and/or delivered will be validly issued, fully paid and non-
assessable, and further agrees to pay all taxes and charges that may be imposed
upon such issuance and/or delivery.

         3. Protection Against Dilution.

         (a) In the event the Company shall, at any time or from time to time
after the date of issuance of this Warrant, issue or distribute to all of the
holders of its shares of Common Stock evidence of its indebtedness, any other
securities of the Company or any cash, property or other assets (any such event
being herein called a "Special Dividend"), the Per Share Exercise Price shall be
adjusted by multiplying the Per Share Exercise Price then in effect by a
fraction, the numerator of which shall be the then Current Market Price (as
defined in paragraph 3(k) below) of the Common Stock, less the Current Market
Price of the Special Dividend issued or distributed in respect of one share of
Common Stock, and the denominator of which shall be the Current Market Price of
the Common Stock. Such adjustment shall be made successively whenever such a
record date is fixed. Such adjustment shall be made whenever any such
distribution is made and shall become effective immediately after the record
date for the determination of shareholders entitled to receive such distribution
unless such distribution is not ultimately made.

         (b) In case the Company shall hereafter (i) pay a dividend or make a
distribution on its capital stock in shares of Common Stock, (ii) subdivide its
outstanding shares of Common Stock into a greater number of shares, (iii)
combine its outstanding shares of Common Stock into a smaller number of shares
or (iv) issue by reclassification of its Common

                                        2

<PAGE>



Stock any shares of capital stock of the Company, the Per Share Exercise Price
shall be adjusted to be equal to a fraction, the numerator of which shall be the
Aggregate Exercise Price and the denominator of which shall be the number of
shares of Common Stock or other capital stock of the Company issuable upon
exercise of this Warrant assuming this Warrant had been exercised immediately
prior to such action. An adjustment made pursuant to this subsection 3(b) shall
become effective immediately after the record date in the case of a dividend or
distribution and shall become effective immediately after the effective date in
the case of a subdivision, combination or reclassification.

         (c)(i) Except as provided in subsections 3(a) and 3(b)(i), in the event
the Company shall hereafter issue or sell any Common Stock, any securities
convertible into Common Stock or any rights, options or warrants to purchase
Common Stock or securities convertible into Common Stock, in each case for a
price per share or entitling the holders thereof to purchase Common Stock at a
price per share (determined by dividing (i) the total amount, if any, received
or receivable by the Company in consideration of the issuance or sale of such
securities plus the consideration, if any, payable to the Company upon exercise
or conversion thereof (collectively, the "Total Consideration") by (ii) the
number of additional shares of Common Stock issued, sold or issuable upon
exercise or conversion of such securities) which is less than the then Current
Market Price of the Common Stock (as defined below) but not below the current
Per Share Exercise Price (which event is governed by subsection 3(c)(ii)), the
Per Share Exercise Price shall be adjusted as of the date of such issuance or
sale by multiplying the Per Share Exercise Price then in effect by a fraction,
the numerator of which shall be (x) the sum of (A) the number of shares of
Common Stock outstanding on the record date of such issuance or sale plus (B)
the Total Consideration divided by the Current Market Price of the Common Stock,
and the denominator of which shall be (y) the number of shares of Common Stock
outstanding on the record date of such issuance or sale plus the maximum number
of additional shares of Common Stock issued, sold or issuable upon exercise or
conversion of such securities.

         (ii) Except as provided in subsection 3(a) and 3(b)(i), in the event
the Company shall hereafter issue or sell any Common Stock, any securities
convertible into Common Stock or any rights, options or warrants to purchase
Common Stock or securities convertible into Common Stock, in each case for a
price per share or entitling the holders thereof to purchase Common Stock at a
price per share (the "Issue Price"), (determined by dividing (i) the Total
Consideration by (ii) the number of additional shares of Common Stock issuable
upon exercise or conversion of such securities) which is less than the then
current Per Share Exercise Price in effect on the record date of such issuance,
the Per Share Exercise Price shall be adjusted to equal the Issue Price.

         (d) In the event of any capital reorganization or reclassification, or
any consolidation or merger to which the Company is a party other than a merger
or consolidation in which the Company is the continuing corporation, or in case
of any sale or conveyance to another entity of the property of the Company as an
entirety or substantially as an entirety, or in the case of any statutory
exchange of securities with another corporation (including any exchange effected
in connection with a merger of a third corporation into the Company), the Holder
of this Warrant shall have the right thereafter to receive on the exercise of
this Warrant the kind and amount of securities, cash or other property which the
Holder would have owned

                                        3

<PAGE>



or have been entitled to receive immediately after such reorganization,
reclassification, consolidation, merger, statutory exchange, sale or conveyance
had this Warrant been exercised immediately prior to the effective date of such
reorganization, reclassification, consolidation, merger, statutory exchange,
sale or conveyance and in any such case, if necessary, appropriate adjustment
shall be made in the application of the provisions set forth in this Section 3
with respect to the rights and interests thereafter of the Holder of this
Warrant to the end that the provisions set forth in this Section 3 shall
thereafter correspondingly be made applicable, as nearly as may reasonably be,
in relation to any shares of stock or other securities or property thereafter
deliverable on the exercise of this Warrant. The above provisions of this
subsection 3(d) shall similarly apply to successive reorganizations,
reclassifications, consolidations, mergers, statutory exchanges, sales or
conveyances. The issuer of any shares of stock or other securities or property
thereafter deliverable on the exercise of this Warrant shall be responsible for
all of the agreements and obligations of the Company hereunder. Notice of any
such reorganization, reclassification, consolidation, merger, statutory
exchange, sale or conveyance and of said provisions so proposed to be made,
shall be mailed to the Holders of the Warrants not less than 30 days prior to
such event. A sale of all or substantially all of the assets of the Company for
a consideration consisting primarily of securities shall be deemed a
consolidation or merger for the foregoing purposes.

         (e) In case any event shall occur as to which the other provisions of
this Section 3 are not strictly applicable but as to which the failure to make
any adjustment would not fairly protect the purchase rights represented by this
Warrant in accordance with the essential intent and principles hereof then, in
each such case, the Holders of Warrants representing the right to purchase a
majority of the Warrant Shares subject to all outstanding Warrants may appoint a
firm of independent public accountants of recognized national standing
reasonably acceptable to the Company, which shall give their opinion as to the
adjustment, if any, on a basis consistent with the essential intent and
principles established herein, necessary to preserve the purchase rights
represented by the Warrants. Upon receipt of such opinion, the Company will
promptly mail a copy thereof to the Holder of this Warrant and shall make the
adjustments described therein. The fees and expenses of such independent public
accountants shall be borne by the Company.

         (f) Whenever the Per Share Exercise Price payable upon exercise of each
Warrant is adjusted pursuant to this Section 3, the number of shares of Common
Stock underlying a Warrant shall simultaneously be adjusted to equal the number
obtained by dividing the Aggregate Exercise Price by the adjusted Per Share
Exercise Price.

         (g) No adjustment in the Per Share Exercise Price shall be required
unless such adjustment would require an increase or decrease of at least $0.01
per share of Common Stock; provided, however, that any adjustments which by
reason of this subsection 3(g) are not required to be made shall be carried
forward and taken into account in any subsequent adjustment. All calculations
under this Section 3 shall be made to the nearest cent or to the nearest 1/100th
of a share, as the case may be. Anything in this Section 3 to the contrary
notwithstanding, the Company shall be entitled to make such reductions in the
Per Share Exercise Price, in addition to those required by this Section 3, as it
in its discretion shall deem to be advisable in order that any stock dividend,
subdivision of shares or distribution of rights

                                        4

<PAGE>



to purchase stock or securities convertible or exchangeable for stock hereafter
made by the Company to its stockholders shall not be taxable.

         (h) Whenever the Per Share Exercise Price is adjusted as provided in
this Section 3 and upon any modification of the rights of a Holder of Warrants
in accordance with this Section 3, the Company shall promptly obtain, at its
expense, a certificate of a firm of independent public accountants of recognized
standing selected by the Board of Directors (who may be the regular auditors of
the Company) setting forth the Per Share Exercise Price and the number of
Warrant Shares after such adjustment or the effect of such modification, a brief
statement of the facts requiring such adjustment or modification and the manner
of computing the same and cause copies of such certificate to be mailed to the
Holders of the Warrants.

         (i) If the Board of Directors of the Company shall declare any dividend
or other distribution with respect to the Common Stock, the Company shall mail
notice thereof to the Holders of the Warrants not less than 30 days prior to the
record date fixed for determining stock holders entitled to participate in such
dividend or other distribution.

         (j) If, as a result of an adjustment made pursuant to this Section 3,
the Holder of any Warrant thereafter surrendered for exercise shall become
entitled to receive shares of two or more classes of capital stock or shares of
Common Stock and other capital stock of the Company, the Board of Directors
(whose determination shall be conclusive and shall be described in a written
notice to the Holder of any Warrant promptly after such adjustment) shall
determine the allocation of the adjusted Per Share Exercise Price between or
among shares or such classes of capital stock or shares of Common Stock and
other capital stock.

         (k) For the purpose of any computation under Section 3 above, the then
Current Market Price per share (the "Current Market Price") shall be deemed to
be the last sale price of the Common Stock on the trading day prior to such date
or, in case no such reported sales take place on such day, the average of the
last reported bid and asked prices of the Common Stock on such day, in either
case on the principal national securities exchange on which the Common Stock is
admitted to trading or listed, or if not listed or admitted to trading on any
such exchange, the representative closing bid price of the Common Stock as
reported by the National Association of Securities Dealers, Inc. Automated
Quotations System ("NASDAQ"), or other similar organization if NASDAQ is no
longer reporting such information, or, if the Common Stock is not reported on
NASDAQ, the high per share bid price for the Common Stock in the
over-the-counter market as reported by the National Quotation Bureau or similar
organization, or if not so available, the fair market value of the Common Stock
as determined by agreement between the Company's Board of Directors, on the one
part, and the Holders of Warrants representing the right to purchase a majority
of the Warrant Shares subject to all outstanding Warrants, on the second part.
If the Board of Directors and such Holders fail to agree on the Current Market
Price within 60 days of the date of the action giving rise to any adjustment
pursuant to this Section 3, such Holders shall be entitled to appoint a firm of
independent public accountants or appraisers of recognized national standing
reasonably acceptable to the Company, which shall give their opinion as to such
Current Market Price on a basis consistent with the essential intent and
principles established herein. Upon receipt of such opinion, the Company will
promptly mail a copy thereof to the Holder of this Warrant and shall

                                        5

<PAGE>



make the adjustments described therein. The fees and expenses of such
independent public accountants or appraisers shall be borne by the Company.

         4. Registration Under Securities Act of 1933 . The resale of the
Warrant Shares shall be registered on the Shelf Registration Statement (as
defined in Article 8 of the Securities Purchase Agreement (the "Purchase
Agreement") dated as of June 30, 1997, by and among the Company, The Aries Fund,
a Cayman Island Trust, and The Aries Domestic Fund, L.P., a Delaware limited
partnership) and certain purchasers and the Holder of this Warrant shall have
the registration rights as provided in Article 8 of the Purchase Agreement. If
the Holder is not a party to the Purchase Agreement, by acceptance of this
Warrant the Holder agrees to comply with provisions of Article 8 of the Purchase
Agreement to the same extent as if it were a party thereto.

         5. Limited Transferability. This Warrant may not be sold, transferred,
assigned or hypothecated by the Holder except in compliance with the provisions
of the Securities Act of 1933 (the "Act") and the applicable state securities
"blue sky" laws, and is so transferable only upon the books of the Company which
it shall cause to be maintained for such purpose. The Company may treat the
registered Holder of this Warrant as he or it appears on the Company's books at
any time as the Holder for all purposes. The Company shall permit any Holder of
a Warrant or his duly authorized attorney, upon written request during ordinary
business hours, to inspect and copy or make extracts from its books showing the
registered holders of Warrants. All Warrants issued upon the transfer or
assignment of this Warrant will be dated the same date as this Warrant, and all
rights of the holder thereof shall be identical to those of the Holder.

         6. Loss, etc., of Warrant. Upon receipt of evidence satisfactory to the
Company of the loss, theft, destruction or mutilation of this Warrant, and of
indemnity reasonably satisfactory to the Company, if lost, stolen or destroyed,
and upon surrender and cancellation of this Warrant, if mutilated, the Company
shall execute and deliver to the Holder a new Warrant of like date, tenor and
denomination.

         7. Status of Holder. This Warrant does not confer upon the Holder any
right to vote or to consent to or receive notice as a stockholder of the
Company, as such, in respect of any matters whatsoever, or any other rights or
liabilities as a stockholder, prior to the exercise hereof.

         8. Notices. No notice or other communication under this Warrant shall
be effective unless, but any notice or other communication shall be effective
and shall be deemed to have been given if, the same is in writing and is mailed
by first-class mail, postage prepaid, addressed to:

          (a) the Company at 840 Memorial Drive, Cambridge, Massachusetts,
     Attention: Stanley C. Erck, or such other address as the Company has
     designated in writing to the Holder; or


                                        6

<PAGE>



          (b) the Holder at the address indicated in the notice provisions to
     the Purchase Agreement, or other such address as the Holder has designated
     in writing to the Company.

         9. Special Adjustments.

         (a) The per share exercise price of this Warrant shall be adjusted at
the time of the Series B Final Closing Date or the closing of the Company's next
Qualified Offering (as these terms are defined in the Letter of Intent between
the Company and Paramount Capital Inc., dated June 30, 1997) if (i) the per
share exercise price of the Offering Warrants (as defined below) or (ii) the
quotient of (a) the price per unit sold in the Series B Offering or other
Qualified Offering divided by (b) the quantity of Common Stock (or any
securities other than Common Stock viewed on a Common Stock equivalent basis,
collectively, the "Other Securities") included in each unit sold in such Series
B Offering or other Qualified Offering, is less than twice the per share
exercise price of this Warrant. In such event the per share exercise price
hereof shall be reduced to equal 50% of the then current per share exercise
price of the Offering Warrants (as hereafter defined) or per share exercise or
offering price of the Other Securities (viewed on a Common Stock equivalent
basis). "Offering Warrants" shall mean the warrants described in paragraph 8 of
the Letter of Intent between the Company the Holders, and Paramount Capital,
Inc. dated June 30, 1997.

         (b) In addition to the foregoing, on June 30, 1998 (the "Reset Date")
the exercise price per share shall be adjusted and reset effective as of the
Reset Date if the Market Price (as defined below) of the Common Stock as of the
Reset Date (the "12-Month Trading Price") is less than 140% of the then
applicable exercise price (a "Reset Event"). Upon the occurrence of a Reset
Event, the exercise price shall be reduced to be equal to the greater of (A) the
12-Month Trading Price divided by 1.40, and (B) 25% of the then applicable
exercise price. "Market Price" shall mean the average reported per share closing
bid price of the Common Stock regular way on the Stock Market for twenty (20)
consecutive trading days, ending with the trading day prior to the Reset Date
or, if there were no transactions on any such trading day, the average of the
reported closing bid and asked prices, regular way, of the Common Stock on the
relevant Stock Market on such trading day (with appropriate adjustments for
subdivisions or combinations of shares effected during such period), provided
that if such trading prices cannot be determined for such period, "Market Price"
shall mean Fair Market Value (as defined below). The "Stock Market" shall mean
the principal national securities exchange on which the Common Stock is listed
or admitted to trading or, if the Common Stock is not listed or admitted to
trading on any national securities exchange, shall mean The Nasdaq National
Market System ("NNM") or The Nasdaq SmallCap Market ("SCM" and, together with
NNM, "Nasdaq") or, if such security is not quoted on Nasdaq, shall mean the OTC
Bulletin Board or, if such security is not quoted on the OTC Bulletin Board,
shall mean the over-the-counter market as furnished by any NASD member firm
selected from time to time by the Company for that purpose. "Fair Market Value"
means the fair market value thereof as mutually determined by the Company and
the holder of this Warrant. If the Company and the holder of this Warrant are
unable to reach agreement on any valuation matter, such valuation shall be
submitted to and determined by a nationally recognized independent investment
bank selected by the Board of Directors and the holder of this Warrant (or, if
such selection cannot be agreed upon promptly, or in any event within ten days,
then such valuation shall be made by a nationally recognized independent

                                        7

<PAGE>



investment banking firm selected by the American Arbitration Association in New
York City in accordance with its rules), the costs of which valuation shall be
paid for by the Company.

         10. Headings. The headings of this Warrant have been inserted as a
matter of convenience and shall not affect the construction hereof.

         11. Applicable Law. This Warrant shall be governed by and construed in
accordance with the law of the State of New York without giving effect to
principles of conflicts of law thereof.

         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its President and its corporate seal to be hereunto affixed and attested by its
Secretary this 30th day of September 1997.


                                     PROCEPT, INC.



                                     By:    /s/ Stanley C. Erck
                                         ------------------------------
                                         Name:  Stanley C. Erck
                                         Title: President


ATTEST:


  /s/ Lynnette C. Fallon
----------------------------
Secretary

[Corporate Seal]


                                        8

<PAGE>


                                  SUBSCRIPTION
                                  ------------

         The undersigned, ____________________________, pursuant to the
provisions of the foregoing Warrant, hereby elects to exercise the within
Warrant to the extent of purchasing _____________________ shares of Common Stock
thereunder and hereby makes payment of $_______________ by certified or official
bank check in payment of the per share exercise price therefor.

Dated:_______________                 Signature:_____________________________

                                      Address:_______________________________


                                   ASSIGNMENT
                                   ----------

         FOR VALUE RECEIVED _______________________________________ hereby
sells, assigns and transfers unto _____________________________________ the
foregoing Warrant and all rights evidenced thereby, and does irrevocably
constitute and appoint _____________________________, attorney, to transfer said
Warrant on the books of Procept, Inc.


Dated:_______________                 Signature:_____________________________

                                      Address:______________________________


                               PARTIAL ASSIGNMENT
                               ------------------

         FOR VALUE RECEIVED __________________________ hereby assigns and
transfers unto _________________________ the right to purchase __________ shares
of the Common Stock, no par value per share, of Procept Inc. covered by the
foregoing Warrant, and a proportionate part of said Warrant and the rights
evidenced thereby, and does irrevocably constitute and appoint
__________________________, attorney, to transfer that part of said Warrant on
the books of Procept, Inc.


Dated:_______________                 Signature:___________________________

                                      Address:_____________________________