UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 12)*

                               Biovail Corporation
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                                (Name of Issuer)

                           Common Stock, no par value
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                         (Title of Class of Securities)

                                    09067K106
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                                 (CUSIP Number)

                                  Eugene Melnyk
                               Biovail Corporation
                              7150 Mississauga Road
                           Mississauga, Ontario L5N8M5
                                     Canada

                                 (905) 286-3000
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       (Name, Address and Telephone Number of Person Authorized to Receive
                           Notices and Communications)

                                 August 6, 2003
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             (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition which is the subject of this Schedule 13D, and is filing this
schedule because of Rule 13d-1(b)(3) or (4), check the following box [ ].

Note: An EDGAR version of this statement, including all exhibits, should be
filed with the Commission. See Rule 13d-1(a) for other parties to whom copies
are to be sent.

* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).

                                  SCHEDULE 13D

CUSIP No. 09067K106
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1     NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

            Eugene Melnyk
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2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                         (a) [ ]
                                                                         (b) [ ]
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3     SEC USE ONLY


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4     SOURCE OF FUNDS

            PF
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5     CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
      ITEMS 2(d) or 2(e)                                                     [ ]

            N/A
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6     CITIZENSHIP OR PLACE OF ORGANIZATION

            Canada
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                        7     SOLE VOTING POWER

                                    27,145,320
                        --------------------------------------------------------
      NUMBER OF         8     SHARED VOTING POWER
       SHARES
    BENEFICIALLY                    190,496
      OWNED BY          --------------------------------------------------------
       EACH             9     SOLE DISPOSITIVE POWER
     REPORTING
      PERSON                        27,145,320
       WITH             --------------------------------------------------------
                        10    SHARED DISPOSITIVE POWER

                                    190,496
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11    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            27,335,816
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12    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* [ ]

            N/A
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13    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

            18.6%
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14    TYPE OF REPORTING PERSON*

            IN
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                      *SEE INSTRUCTIONS BEFORE FILLING OUT!
          INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7
             (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE
                                  ATTESTATION.



                                      2

      This Amendment No. 12 amends and supplements the statement on Schedule 13D
filed with the Securities and Exchange Commission (the "SEC") on March 30, 1994,
as amended by Amendment No. 1 thereto filed with the SEC on April 11, 1995,
Amendment No. 2 thereto filed with the SEC on September 25, 1996, Amendment No.
3 thereto filed with the SEC on March 11, 1997, Amendment No. 4 thereto filed
with the SEC on May 6, 1997, Amendment No. 5 thereto filed with the SEC on
January 13, 1998, Amendment No. 6 thereto filed with the SEC on March 26, 1998,
Amendment No. 7 thereto filed with the SEC on September 28, 2001, Amendment No.
8 thereto filed with the SEC on January 15, 2002, Amendment No.9 thereto
relating to the event date of February 1, 2002, Amendment No.10 thereto relating
to the event date of May 8, 2002 and Amendment No. 11 thereto relating to the
event date of November 28, 2002 (as so amended, the "Schedule 13D"), with
respect to the common stock, no par value (the "Common Stock"), of Biovail
Corporation (the "Company"). Except as amended by this Amendment No. 12, the
Schedule 13D, as heretofore filed with the SEC, shall remain in full force and
effect.

ITEM 1.     SECURITY AND ISSUER.

            This amendment relates to the Common Stock of the Company.

ITEM 2.     IDENTITY AND BACKGROUND.

            This amendment is being filed by Eugene Melnyk, the Chairman of the
Board and a director of the Company. The filing of this amendment shall not be
construed as an admission that Mr. Melnyk is, for purposes of Section 13(d) or
13(g) of the Securities Exchange Act of 1934, as amended, the beneficial owner
of any securities reported on herein except for the securities stated herein to
be beneficially owned by Mr. Melnyk.

ITEM 3.     SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

            See Schedule A for a description of Mr. Melnyk's transactions
involving Common Stock during the past 60 days.

ITEM 4.     PURPOSE OF TRANSACTION.

            Mr. Melnyk's acquisition of the securities of the Company was for
the purpose of investment. However, the Mr. Melnyk retains his right to acquire
shares of Common Stock and to dispose of shares of Common Stock. In determining
whether to purchase or dispose of shares of Common Stock, Mr. Melnyk intends to
consider and review various factors on a continuous basis, including the
Company's financial condition, business and prospects, other developments
concerning the Company, the price and availability of shares of Common Stock,
other investment and business opportunities available to Mr. Melnyk, and
developments with respect to general economic, monetary and stock market
conditions.

            Except as otherwise described herein, Mr. Melnyk has no plan or
proposal with respect to the Company which relates to or would result in any of
the matters listed in Items 4(a) - (j) of Schedule 13D. However, in addition to
the rights reserved above, the Mr. Melnyk retains his rights to modify his plans
with respect to the transactions described in this Item 4, to acquire


                                       3

or dispose of securities of the Company and to formulate plans and proposals
which could result in the occurrence of any such events, subject to applicable
laws and regulations.

ITEM 5.     INTEREST IN SECURITIES OF THE ISSUER.

            (a) As of August 14, 2003, Mr. Melnyk may be deemed to be the
beneficial owner of 27,335,816 shares of Common Stock (including 25,516,220
shares that are owned directly by Mr. Melnyk, 95,100 shares held by the Eugene
Melnyk Registered Retirement Savings Plan, 190,496 shares held by Laura Melnyk
(Mr. Melnyk's wife), 1,534,000 shares which are subject to options exercisable
within 60 days held by Mr. Melnyk, which constitute in the aggregate 18.6% of
the shares of Common Stock outstanding. In addition, Mr. Melnyk owns options to
purchase 563,700 shares of Common Stock which are not exercisable within 60 days
of the date of this amendment.

            Except as described in the preceding paragraph, Mr. Melnyk does not
beneficially own any shares of Common Stock.

            (b) Except as set forth in the next sentence, Mr. Melnyk has the
sole power to vote, direct the voting of, dispose of and direct the disposition
of the Common Stock beneficially owned by him. Mr. Melnyk shares with Laura
Melnyk (his wife) the power to vote, direct the voting of, dispose of and direct
the disposition of the Common Stock beneficially held by her.

            (c) See Schedule A for a description of Mr. Melnyk's transactions in
Common Stock during the past 60 days.

            (d) Mr. Melnyk has the sole right to receive or the power to direct
the receipt of dividends from, or the proceeds from the sale of, the Common
Stock owned by him.

            (e) Not applicable.

ITEM 6.     CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH
            RESPECT TO SECURITIES OF THE ISSUER.

            Not applicable.

ITEM 7.     MATERIAL TO BE FILED AS EXHIBITS.

            Not applicable.


                                       4

                                    SIGNATURE

            After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true, complete and
correct.

August 14, 2003


                                            /s/ Eugene Melnyk
                                            ---------------------
                                            Eugene Melnyk






                                       5

                                   Schedule A

               Transactions in Common Stock in the last 60 days(1)



                                                             Number of Shares
        Date and Type               Price Per Share          of Common Stock
        -------------               ---------------          ----------------
                                                       
         8/6/03 Sale                    C$ 52.90                  10,000
         8/6/03 Sale                    C$ 52.48                    700
         8/6/03 Sale                    C$ 52.40                  22,600
         8/6/03 Sale                    C$ 52.37                   1,600
         8/6/03 Sale                    C$ 52.35                   2,800
         8/6/03 Sale                    C$ 52.57                    800
         8/6/03 Sale                    C$ 52.55                   9,200
         8/6/03 Sale                    C$ 52.50                    100
         8/6/03 Sale                    C$ 52.30                   9,900
         8/6/03 Sale                    C$ 52.75                   3,000
         8/6/03 Sale                    C$ 52.55                   4,000
         8/6/03 Sale                    C$ 52.41                   1,000
         8/6/03 Sale                    C$ 52.60                  10,000
         8/6/03 Sale                    C$ 53.02                    300
         8/6/03 Sale                    C$ 53.00                   9,700
         8/6/03 Sale                    C$ 52.51                   1,500
         8/6/03 Sale                    C$ 52.50                   2,800
         8/6/03 Sale                    C$ 52.35                   1,100
         8/6/03 Sale                    C$ 52.30                   8,900



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(1) All transactions effected in the open market.


                                       6


                                                       
    8/6/03 Purchase Call(2)              $ 4.20                   24,700
    8/6/03 Purchase Call(2)              $ 4.00                   20,000
    8/6/03 Purchase Call(2)              $ 4.10                   40,400
    8/6/03 Purchase Call(2)              $ 4.40                   14,900
         8/7/03 Sale                    C$ 52.50                  30,000
         8/7/03 Sale                    C$ 52.56                  10,000
         8/7/03 Sale                    C$ 53.00                   8,400
         8/7/03 Sale                    C$ 53.03                   1,600
         8/7/03 Sale                    C$ 53.20                  10,000
         8/7/03 Sale                    C$ 53.40                   6,800
         8/7/03 Sale                    C$ 53.31                   1,000
         8/7/03 Sale                    C$ 53.29                    200
         8/7/03 Sale                    C$ 53.27                    300
         8/7/03 Sale                    C$ 53.26                    300
         8/7/03 Sale                    C$ 53.24                   1,400
         8/7/03 Sale                    C$ 53.15                   1,500
         8/7/03 Sale                    C$ 53.10                   8,000
         8/7/03 Sale                    C$ 53.05                    500
         8/7/03 Sale                    C$ 53.01                  10,000
         8/7/03 Sale                    C$ 52.95                  10,000
    8/7/03 Purchase Call(2)              $ 4.30                   10,000
    8/7/03 Purchase Call(2)              $ 4.40                   30,000
    8/7/03 Purchase Call(2)              $ 4.60                   10,000


------------------
(2) Represents purchase of immediately exercisable call option to acquire the
number of shares listed at an exercise price of $40.00 per share. Call options
expire 1/17/04.


                                       7



                                                       
    8/7/03 Purchase Call(2)              $ 4.70                   41,000
    8/7/03 Purchase Call(2)              $ 4.80                    9,000
         8/8/03 Sale                    C$ 54.60                   6,000
         8/8/03 Sale                    C$ 54.50                   4,000
         8/8/03 Sale                    C$ 55.00                  10,000
         8/8/03 Sale                    C$ 55.10                  15,000
         8/8/03 Sale                    C$ 55.25                  10,000
         8/8/03 Sale                    C$ 55.30                  20,000
         8/8/03 Sale                    C$ 55.45                   5,000
         8/8/03 Sale                    C$ 55.05                  10,000
         8/8/03 Sale                    C$ 54.55                  20,000
    8/8/03 Purchase Call(2)              $ 5.30                   10,000
    8/8/03 Purchase Call(2)              $ 5.50                   10,000
    8/8/03 Purchase Call(2)              $ 5.60                   23,200
    8/8/03 Purchase Call(2)              $ 5.70                   12,800
    8/8/03 Purchase Call(2)              $ 5.80                   34,000
    8/8/03 Purchase Call(2)              $ 5.90                   10,000



                                       8