<PAGE>
                                                                     Exhibit 4.1



THIS NOTE AND THE COMMON SHARES ISSUABLE UPON CONVERSION OF THIS NOTE HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THIS NOTE AND THE
COMMON SHARES ISSUABLE UPON CONVERSION OF THIS NOTE MAY NOT BE SOLD, OFFERED FOR
SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
STATEMENT AS TO THIS NOTE UNDER SAID ACT OR AN OPINION OF COUNSEL REASONABLY
SATISFACTORY TO EMPYREAN BIOSCIENCE, INC., THAT SUCH REGISTRATION IS NOT
REQUIRED.

                                CONVERTIBLE NOTE
                                ----------------

     FOR VALUE RECEIVED, EMPYREAN BIOSCIENCE, INC., a Delaware corporation
(hereinafter called "Borrower"), hereby promises to pay to LAURUS MASTER FUND,
LTD., c/o Onshore Corporate Services Ltd., P.O. Box 1234 G.T., Queensgate House,
South Church Street, Grand Cayman, Cayman Islands, Fax: 345-949-9877 (the
"Holder") on order, without demand, the sum of Two Hundred Fifty Thousand
Dollars ($250,000.00), with simple interest accruing at the annual rate of 8%,
on August 23, 2003 (the "Maturity Date").

     The following terms shall apply to this Note:

                                    ARTICLE I

                           DEFAULT RELATED PROVISIONS

     1.1 PAYMENT GRACE PERIOD. The Borrower shall have a ten (10) day grace
period to pay any monetary amounts due under this Note, after which grace period
a default interest rate of twenty percent (20%) per annum shall apply to the
amounts owed hereunder.

     1.2 CONVERSION PRIVILEGES. The Conversion Privileges set forth in Article
II shall remain in full force and effect immediately from the date hereof and
until the Note is paid in full.

     1.3 INTEREST RATE. Subject to the Holder's right to convert, interest
payable on this Note shall accrue at the annual rate of eight percent (8%) and
be payable in arrears commencing September 30, 2001 and quarterly thereafter,
and on the Maturity Date, accelerated or otherwise, when the principal and
remaining accrued but unpaid interest shall be due and payable, or sooner as
described below. The Company will deliver accrued but unpaid interest on the
Note either in cash or in stock, at the option of the Company, through the
Conversion Date directly to the Holder on or before the Delivery Date (as
defined in the Subscription Agreement).



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                                   ARTICLE II

                                CONVERSION RIGHTS

     The Holder shall have the right to convert the principal amount and
interest due under this Note into Shares of the Borrower's Common Stock as set
forth below.

     2.1. CONVERSION INTO THE BORROWER'S COMMON STOCK.

     (a) The Holder shall have the right from and after the issuance of this
Note and then at any time until this Note is fully paid, to convert any
outstanding and unpaid principal portion of this Note, and/or at the Company's
option, the interest accrued on the Note, (the date of giving of such notice of
conversion being a "Conversion Date") into fully paid and nonassessable shares
of common stock of Borrower as such stock exists on the date of issuance of this
Note, or any shares of capital stock of Borrower into which such stock shall
hereafter be changed or reclassified (the "Common Stock") at the conversion
price as defined in Section 2.1(b) hereof (the "Conversion Price"), determined
as provided herein. Upon delivery to the Company of a Notice of Conversion as
described in Section 9 of the subscription agreement entered into between the
Company and Holder relating to this Note (the "Subscription Agreement") of the
Holder's written request for conversion, Borrower shall issue and deliver to the
Holder within five (5) business days from the Conversion Date that number of
shares of Common Stock for the portion of the Note converted in accordance with
the foregoing. The number of shares of Common Stock to be issued upon each
conversion of this Note shall be determined by dividing that portion of the
principal of the Note to be converted and interest, if any, by the Conversion
Price.

     (b) Subject to adjustment as provided in Section 2.1(c) hereof, the
Conversion Price per share shall be the lower of (i) eighty percent (80%) of the
average of the three lowest closing prices for the Common Stock on the NASD OTC
Bulletin Board, NASDAQ SmallCap Market, NASDAQ National Market System, American
Stock Exchange, or New York Stock Exchange (whichever of the foregoing is at the
time the principal trading exchange or market for the Common Stock, the
"Principal Market"), or if not then trading on a Principal Market, such other
principal market or exchange where the Common Stock is listed or traded, for the
thirty (30) trading days prior to but not including the Closing Date (as defined
in the Subscription Agreement) in connection with which this Note is issued
("Maximum Base Price"); or (ii) eighty percent (80%) of the average of the three
lowest closing prices for the Common Stock on the Principal Market, or on any
securities exchange or other securities market on which the Common Stock is then
being listed or traded, for the sixty (60) trading days prior to but not
including the Conversion Date.

     (c) The Maximum Base Price described in Section 2.1(b)(i) above and number
and kind of shares or other securities to be issued upon conversion determined
pursuant to Section 2.1(a) and 2.1(b), shall be subject to adjustment from time
to time upon the happening of certain events while this conversion right remains
outstanding, as follows:



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          A. Merger, Sale of Assets, etc. If the Borrower at any time shall
consolidate with or merge into or sell or convey all or substantially all its
assets to any other corporation, this Note, as to the unpaid principal portion
thereof and accrued interest thereon, shall thereafter be deemed to evidence the
right to purchase such number and kind of shares or other securities and
property as would have been issuable or distributable on account of such
consolidation, merger, sale or conveyance, upon or with respect to the
securities subject to the conversion or purchase right immediately prior to such
consolidation, merger, sale or conveyance. The foregoing provision shall
similarly apply to successive transactions of a similar nature by any such
successor or purchaser. Without limiting the generality of the foregoing, the
anti-dilution provisions of this Section shall apply to such securities of such
successor or purchaser after any such consolidation, merger, sale or conveyance.

          B. Reclassification, etc. If the Borrower at any time shall, by
reclassification or otherwise, change the Common Stock into the same or a
different number of securities of any class or classes, this Note, as to the
unpaid principal portion thereof and accrued interest thereon, shall thereafter
be deemed to evidence the right to purchase an adjusted number of such
securities and kind of securities as would have been issuable as the result of
such change with respect to the Common Stock immediately prior to such
reclassification or other change.

          C. Stock Splits, Combinations and Dividends. If the shares of Common
Stock are subdivided or combined into a greater or smaller number of shares of
Common Stock, or if a dividend is paid on the Common Stock in shares of Common
Stock, the Conversion Price shall be proportionately reduced in case of
subdivision of shares or stock dividend or proportionately increased in the case
of combination of shares, in each such case by the ratio which the total number
of shares of Common Stock outstanding immediately after such event bears to the
total number of shares of Common Stock outstanding immediately prior to such
event.

          D. Share Issuance. Subject to the provisions of this Section, if the
Borrower at any time shall issue any shares of Common Stock prior to the
conversion of the entire principal amount of the Note (otherwise than as: (i)
provided in Sections 2.1(c)A, 2.1(c)B or 2.1(c)C or this subparagraph D; (ii)
pursuant to options, warrants, or other obligations to issue shares, outstanding
on the date hereof as described in the Reports and Other Written Information, as
such terms are defined in the Subscription Agreement (which agreement is
incorporated herein by this reference); or (iii) Excepted Issuances, as defined
in Section 12 of the Subscription Agreement; ((i), (ii) and (iii) above, are
hereinafter referred to as the "Existing Option Obligations") for a
consideration less than the Conversion Price that would be in effect at the time
of such issue, then, and thereafter successively upon each such issue, the
Conversion Price shall be reduced as follows: (i) the number of shares of Common
Stock outstanding immediately prior to such issue shall be multiplied by the
Conversion Price in effect at the time of such issue and the product shall be
added to the aggregate consideration, if any, received by the Borrower upon such
issue of additional shares of Common Stock; and (ii) the sum so obtained shall
be divided by the number of shares of Common Stock outstanding immediately after
such issue. The resulting quotient shall be the adjusted conversion price.
Except for the Existing Option Obligations, for purposes of this adjustment, the
issuance of any security of



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the Borrower carrying the right to convert such security into shares of Common
Stock or of any warrant, right or option to purchase Common Stock shall result
in an adjustment to the Conversion Price upon the issuance of shares of Common
Stock upon exercise of such conversion or purchase rights.

     (d) During the period the conversion right exists, Borrower will reserve
from its authorized and unissued Common Stock a sufficient number of shares to
provide for the issuance of Common Stock upon the full conversion of this Note.
Borrower represents that upon issuance, such shares will be duly and validly
issued, fully paid and non-assessable. Borrower agrees that its issuance of this
Note shall constitute full authority to its officers, agents, and transfer
agents who are charged with the duty of executing and issuing stock certificates
to execute and issue the necessary certificates for shares of Common Stock upon
the conversion of this Note.

     2.2 METHOD OF CONVERSION. This Note may be converted by the Holder in whole
or in part as described in Section 2.1(a) hereof and the Subscription Agreement.
Upon partial conversion of this Note, a new Note containing the same date and
provisions of this Note shall, at the request of the Holder, be issued by the
Borrower to the Holder for the principal balance of this Note and interest which
shall not have been converted or paid.

                                   ARTICLE III

                                EVENT OF DEFAULT

     The occurrence of any of the following events of default ("Event of
Default") shall, at the option of the Holder hereof, make all sums of principal
and interest then remaining unpaid hereon and all other amounts payable
hereunder immediately due and payable, all without demand, presentment or
notice, or grace period, all of which hereby are expressly waived, except as set
forth below:

     3.1 FAILURE TO PAY PRINCIPAL OR INTEREST. The Borrower fails to pay any
installment of principal or interest hereon when due and such failure continues
for a period of ten (10) days after the due date. The ten (10) day period
described in this Section 3.1 is the same ten (10) day period described in
Section 1.1 hereof.

     3.2 BREACH OF COVENANT. The Borrower breaches any material covenant or
other material term or condition of this Note in any material respect and such
breach, if subject to cure, continues for a period of thirty (30) days after
written notice to the Borrower from the Holder.

     3.3 BREACH OF REPRESENTATIONS AND WARRANTIES. Any material representation
or warranty of the Borrower made herein, in the Subscription Agreement entered
into by the Holder and Borrower in connection with this Note, or in any
agreement, statement or certificate given in writing pursuant hereto or in
connection therewith shall be false or misleading in any material respect.


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     3.4 RECEIVER OR TRUSTEE. The Borrower shall make an assignment for the
benefit of creditors, or apply for or consent to the appointment of a receiver
or trustee for it or for a substantial part of its property or business; or such
a receiver or trustee shall otherwise be appointed.

     3.5 JUDGMENTS. Any money judgment, writ or similar final process shall be
entered or filed against Borrower or any of its property or other assets for
more than $100,000, and shall remain unvacated, unbonded or unstayed for a
period of forty-five (45) days.

     3.6 BANKRUPTCY. Bankruptcy, insolvency, reorganization or liquidation
proceedings or other proceedings or relief under any bankruptcy law or any law
for the relief of debtors shall be instituted by or against the Borrower and if
instituted against Borrower are not dismissed within 45 days of initiation.

     3.7 DELISTING. Delisting of the Common Stock from the NASDAQ SmallCap
Market (unless a listing is obtained on the OTC Bulletin Board within three
trading days of such delisting) or delisting from such other principal exchange
on which the Common Stock is listed for trading; Borrower's failure to comply
with the requirements of the Principal Market for continued listing for a period
of three consecutive trading days; or notification from the Principal Market
that the Borrower is not in compliance with the conditions for such continued
listing.

     3.8 CONCESSION. A concession by the Borrower, after applicable notice and
cure periods, under any one or more obligations in an aggregate monetary amount
in excess of $100,000.

     3.9 STOP TRADE. An SEC stop trade order or Principal Market trading
suspension that lasts for five or more trading days.

     3.10 FAILURE TO DELIVER COMMON STOCK OR REPLACEMENT NOTE. Borrower's
failure to timely deliver Common Stock to the Holder pursuant to and in the form
required by this Note and Section 9 of the Subscription Agreement, or if
required a replacement Note.

     3.11 REGISTRATION DEFAULT. The occurrence of a Non-Registration Event as
described in Section 10.4 of the Subscription Agreement.

                                   ARTICLE IV

                                  MISCELLANEOUS

     4.1 FAILURE OR INDULGENCE NOT WAIVER. No failure or delay on the part of
Holder hereof in the exercise of any power, right or privilege hereunder shall
operate as a waiver thereof, nor shall any single or partial exercise of any
such power, right or privilege preclude other or further exercise thereof or of




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any other right, power or privilege. All rights and remedies existing hereunder
are cumulative to, and not exclusive of, any rights or remedies otherwise
available.

     4.2 NOTICES. Any notice herein required or permitted to be given shall be
in writing and may be personally served or sent by fax transmission (with copy
sent by regular, certified or registered mail or by overnight courier). For the
purposes hereof, the address and fax number of the Holder is as set forth on the
first page hereof. The address and fax number of the Borrower shall be Empyrean
Bioscience, Inc., 23800 Commerce Park Road, Suite A, Cleveland, Ohio 44122,
telecopier number: (216) 360-7909. Both Holder and Borrower may change the
address and fax number for service by service of notice to the other as herein
provided. Notice of Conversion shall be deemed given when made to the Company
pursuant to the Subscription Agreement.

     4.3 AMENDMENT PROVISION. The term "Note" and all reference thereto, as used
throughout this instrument, shall mean this instrument as originally executed,
or if later amended or supplemented, then as so amended or supplemented.

     4.4 ASSIGNABILITY. This Note shall be binding upon the Borrower and its
successors and assigns, and shall inure to the benefit of the Holder and its
successors and assigns, and may be assigned by the Holder.

     4.5 COST OF COLLECTION. If default is made in the payment of this Note,
Borrower shall pay the Holder hereof reasonable costs of collection, including
reasonable attorneys' fees.

     4.6 GOVERNING LAW. This Note shall be governed by and construed in
accordance with the laws of the State of New York. Any action brought by either
party against the other concerning the transactions contemplated by this
Agreement shall be brought only in the state courts of New York or in the
federal courts located in the state of New York. Both parties and the individual
signing this Agreement on behalf of the Borrower agree to submit to the
jurisdiction of such courts. The prevailing party shall be entitled to recover
from the other party its reasonable attorney's fees and costs.

     4.7 MAXIMUM PAYMENTS. Nothing contained herein shall be deemed to establish
or require the payment of a rate of interest or other charges in excess of the
maximum permitted by applicable law. In the event that the rate of interest
required to be paid or other charges hereunder exceed the maximum permitted by
such law, any payments in excess of such maximum shall be credited against
amounts owed by the Borrower to the Holder and thus refunded to the Borrower.

     4.8 PREPAYMENT. This Note may not be paid prior to the Maturity Date or
after the occurrence of an Event of Default without the consent of the Holder
except as set forth in Section 9.7 of the Subscription Agreement.

         [THIS SPACE INTENTIONALLY LEFT BLANK]



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     IN WITNESS WHEREOF, Borrower has caused this Note to be signed in its name
by its Chief Executive Officer on this 23rd day of August, 2001.


                                     EMPYREAN BIOSCIENCE, INC.


                                     By: /s/ Richard C. Adamany, President
                                         ---------------------------------------




WITNESS:



/s/ Bennett S. Rubin
--------------------------------





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                              NOTICE OF CONVERSION
                              --------------------

(To be executed by the Registered Holder in order to convert the Note)


     The undersigned hereby elects to convert $_________ of the principal and
$_________ of the interest due on the Note issued by EMPYREAN BIOSCIENCE, INC.
on August 23, 2001 into Shares of Common Stock of EMPYREAN BIOSCIENCE, INC. (the
"Company") according to the conditions set forth in such Note, as of the date
written below.


Date of Conversion:_____________________________________________________________


Conversion Price:_______________________________________________________________


Shares To Be Delivered:_________________________________________________________


Signature:______________________________________________________________________


Print Name:_____________________________________________________________________


Address:________________________________________________________________________

        ________________________________________________________________________






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