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                                                                    EXHIBIT 10.4

                                 PROMISSORY NOTE

$200,000                                                      NEW YORK, NEW YORK
                                                               DECEMBER 14, 2001

         FOR VALUE RECEIVED, Advanced Viral Research Corp. ("Maker") promises to
pay to the order of Alan Gallantar ("Holder") at 119 E. Hartsdale Avenue,
Hartsdale, NY 10530, the principal sum of Two Hundred Thousand Dollars
($200,000).

         The unpaid principal amount hereof from time to time outstanding shall
bear interest at a rate per annum equal to the Prime Rate (as hereinafter
defined) from time to time in effect. Accrued interest shall be payable on the
first business day of each year and at maturity, beginning with the first
business day of January, 2002. The term "Prime Rate" shall mean, as of any point
in time, the rate of interest then most recently announced by Chase Bank as its
prime rate; and the applicable interest rate under this Note shall change
simultaneously with each change in the Prime Rate. Interest shall be computed
for the actual number of days elapsed on the basis of a year consisting of 365,
or when appropriate, 366 days.

         SUBSEQUENT TO December 3, 2001, PRINCIPAL AND ACCRUED AND UNPAID
INTEREST HEREUNDER SHALL BE DUE UPON DEMAND. NOTWITHSTANDING THE FOREGOING, UPON
RECEIPT OF THE MAKER OF DEBT OR EQUITY FINANCING AFTER THE DATE HEREOF, MAKER
SHALL PAY ALL PRINCIPAL AND ACCRUED AND UNPAID INTEREST DUE TO HOLDER FROM THE
PROCEEDS OF SUCH FINANCING.

         All payments hereunder shall be made in lawful money of the United
States of America at the address of the Holder, or at such other place as the
Holder hereof may designate in writing.

         This Note shall be prepayable in whole or in part without penalty or
premium. This Note will be considered in default upon the failure of the
undersigned to fully, faithfully and punctually perform any of its obligations
under this Note. The "Default Interest Rate" shall be the Prime Rate plus zero
percent (0%) per annum.

         All indebtedness outstanding under this Note after demand shall bear
interest at the Default Interest Rate.

         Maker shall have no obligation to pay interest or payments in the
nature of interest in excess of the maximum rate of interest allowed to be
contracted for by law, as changed from time to time, applicable to this Note
(the "Maximum Rate"). Any interest in excess of the Maximum Rate paid by Maker
("excess sum") shall be credited as a payment of principal, or, if Maker so
requests in writing, returned to Maker, or, if the indebtedness and other
obligations evidenced by this Note have been paid in full, returned to Maker
together with interest at the same rate as was paid by Maker during such period.
Any excess sum credited to principal shall be credited as of the date paid to
Holder.

         Time is of the essence hereunder. In the event that this Note is
collected by law or through attorneys at law, or under advice therefrom, Maker
agrees to pay all reasonable costs of collection, including reasonable
attorneys' fees and paralegals' fees, whether or not suit is brought, and
whether incurred in connection with collection, trial, appeal, bankruptcy or
other creditors' proceedings or otherwise.

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         The remedies of Holder shall be cumulative and concurrent, and may be
pursued singularly, successively or together, at the sole discretion of Holder,
and may be exercised as often as occasion therefor shall arise. No action or
omission of Holder, including specifically any failure to exercise or
forbearance in the exercise of any remedy, shall be deemed to be a waiver or
release of the same, such waiver or release to be effected only through a
written document executed by Holder and then only to the extent specifically
recited therein. A waiver or release with reference to any one event shall not
be construed as continuing or as constituting a course of dealing, nor shall it
be construed as a bar to, or as a waiver or release of, any subsequent remedy as
to a subsequent event.

         This Note is to be governed by and construed under the laws of the
State of New York, as amended.

         Whenever the context so requires, the neuter gender includes the
feminine and/or masculine, as the case may be, and the singular number includes
the plural, and the plural number includes the singular.

         Maker and any other person liable for the payment hereof respectively,
hereby (a) expressly waive any valuation and appraisal, presentment, demand for
payment, notice of dishonor, protest, notice of nonpayment or protest, all other
forms of notice whatsoever, and diligence in collection; (b) consent that Holder
may, from time to time and without notice to any of them or demand, (i) extend,
rearrange, renew or postpone any or all payments, (ii) release, exchange, add to
or substitute all or any part of the collateral for this Note, and/or (iii)
release Maker (or any co-maker) or any other person liable for payment hereof,
without in any way modifying, altering, releasing, affecting or limiting their
respective liability or the lien of any security instrument; and (c) agree that
Holder, in order to enforce payment of this Note against any of them, shall not
be required first to institute any suit or to exhaust any of its remedies
against Maker (or any co-maker) or against any other person liable for payment
hereof or to attempt to realize on any collateral for this Note.

         IN WITNESS WHEREOF, Maker has executed this Note on the day and year
first above written.

                                        ADVANCED VIRAL RESEARCH CORP.

                                        By:  /s/ Shalom Z. Hirschman
                                             -----------------------------------
                                        Name: Shalom Z. Hirschman, M.D.
                                        Title: Chief Executive Officer


                                       2

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                                PERSONAL GUARANTY

         The undersigned Guarantor(s) unconditionally guarantee to the Holder,
its successors and assigns, all sums due and owing from time to time under the
aforementioned Note (the "Guaranteed Amount").

         The Guarantor(s) hereby agree that the terms, covenants and provisions
contained in the the Note and/or in any and all related or pertinent instruments
of whatsoever nature, may be altered, extended, changed, modified, released,
canceled or terminated, all without notice to or consent of the Guarantor(s).
The Guarantor(s) further agree that this Guaranty and the liability of the
Guarantor(s) hereunder shall in no way be affected, diminished or released by
any alterations, extensions, changes, modifications, terminations, releases or
cancellations so made.

         The Guarantor(s) hereby waive any and all legal requirements that the
Holder or its successors or assigns institute any action or proceeding at law or
in equity against the Maker, or exhaust its or their remedies against the Maker
or any security or collateral as a condition precedent to bringing an action
against the Guarantor(s) under this Guaranty. All remedies afforded to the
Holder, its successors or assigns, by reason of this Guaranty are separate
remedies which are in addition to all other remedies possessed by Holder, and it
is agreed that no one of such remedies, whether or not exercised by the Holder
or its successors or assigns, shall be a defense to the Guarantor(s), nor shall
the exercise or failure to so exercise any rights or remedies be deemed a waiver
of any such rights or remedies or an exclusion of any available rights or
remedies which the Holder or its successors or assigns may have at any time
hereunder or otherwise.

         This Guaranty is irrevocable and shall remain in full force and effect
until such time as the Guaranteed Amount has been fully paid for as required
hereby, and thereafter terminated. This Guaranty shall be reinstated if, and to
the extent that, any payments representing the Guaranteed Amount are set aside
and required to be returned by Holder pursuant to an order of a court of
competent jurisdiction.

                                            GUARANTOR(S):

                                            /s/ Shalom Z. Hirschman
                                            -----------------------
                                            Shalom Z. Hirschman, M.D.