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                                                                     EXHIBIT 4.1

                          REGISTRATION RIGHTS AGREEMENT

     AGREEMENT dated as of December 3, 2004, between MERCATOR MOMENTUM FUND, LP,
and MERCATOR MOMENTUM FUND III, LP. (collectively, the "Fund") and MERCATOR
ADVISORY GROUP, LLC ("MAG") (the Fund and MAG are referred to individually as a
"Holder" and collectively as the "Holders"), and Medical Discoveries, Inc., a
Utah corporation (the "Company").

     WHEREAS, the Funds have purchased, for an aggregate of $3,000,000, an
aggregate of 30,000 shares of Series A Convertible Preferred Stock (the "Series
A Stock") from the Company, and have the right to cause their Series A Stock to
be converted into shares of Common Stock, no par value (the "Common Stock"), of
the Company, pursuant to the conversion formula set forth in the Certificate of
Determination;

     WHEREAS, each of Fund and MAG have acquired Warrants (together, the
"Warrants") from the Company, pursuant to which the Holders have the right to
purchase in the aggregate up to 22,877,478 shares of the Common Stock through
the exercise of the Warrants;

     WHEREAS, the Company desires to grant to the Holders the registration
rights set forth herein with respect to the shares of Common Stock issuable upon
the conversion of the Series A Stock and the exercise of the Warrants.

     NOW, THEREFORE, the parties hereto mutually agree as follows:

     1.     REGISTRABLE SECURITIES. As used herein the terms "Registrable
          Security" means each of the shares of Common Stock (i) issued upon the
          conversion of the Series A Stock (the "Conversion Shares") or (ii)
          upon exercise of the Warrants (the "Warrant Shares"), provided,
          however, that with respect to any particular Registrable Security,
          such security shall cease to be a Registrable Security when, as of the
          date of determination that (a) it has been effectively registered
          under the Securities Act of 1933, as amended (the "Securities Act"),
          and disposed of pursuant thereto, or (b) registration under the
          Securities Act is no longer required for the immediate public
          distribution of such security. The term "Registrable Securities" means
          any and/or all of the securities falling within the foregoing
          definition of a "Registrable Security." In the event of any merger,
          reorganization, consolidation, recapitalization or other change in
          corporate structure affecting the Common Stock, such adjustment shall
          be made in the definition of "Registrable Security" as is appropriate
          in order to prevent any dilution or enlargement of the rights granted
          pursuant to this Section 1.

     2.     REGISTRATION.

     The Company shall file a registration statement (the "Registration
Statement") with the Securities and Exchange Commission (the "SEC") on or before
December 15, 2004, in order to register the resale of the Registrable Securities
under the Securities Act. Once effective, the Company shall maintain the
effectiveness of the Registration Statement until the earlier of

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(i) the date that all of the Registrable Securities have been sold, or (ii)
the date that the Company receives an opinion of counsel to the Company that all
of the Registrable Securities may be freely traded without registration under
the Securities Act, under Rule 144 promulgated under the Securities Act or
otherwise.

     The Company will initially include in the Registration Statement as
Registrable Securities Eighty-Two Million Eight Hundred Seventy-Seven Thousand
Four Hundred Seventy-Eight (82,877,478) shares of Common Stock issuable upon
conversion of the Series A Stock and the maximum number of shares of Common
Stock issuable upon exercise of the Warrants.

     3.     COVENANTS OF THE COMPANY WITH RESPECT TO REGISTRATION.

     The Company covenants and agrees as follows:

     The Company shall use best efforts to cause the Registration Statement to
become effective with the SEC as promptly as possible and in no event more than
120 days after the date of this Agreement. If any stop order shall be issued by
the SEC in connection therewith, the Company shall use best efforts to obtain
promptly the removal of such order. Following the effective date of the
Registration Statement, the Company shall, upon the request of any Holder,
forthwith supply such reasonable number of copies of the Registration Statement,
preliminary prospectus and prospectus meeting the requirements of the Securities
Act, and any other documents necessary or incidental to the public offering of
the Registrable Securities, as shall be reasonably requested by the Holder to
permit the Holder to make a public distribution of the Holder's Registrable
Securities. The obligations of the Company hereunder with respect to the
Holder's Registrable Securities are subject to the Holder's furnishing to the
Company such appropriate information concerning the Holder, the Holder's
Registrable Securities and the terms of the Holder's offering of such
Registrable Securities as the Company may reasonably request in writing.

     The Company shall pay all costs, fees and expenses in connection with the
Registration Statement filed pursuant to Section 2 hereof including, without
limitation, the Company's legal and accounting fees, printing expenses, and blue
sky fees and expenses; provided, however, that each Holder shall be solely
responsible for the fees of any counsel retained by the Holder in connection
with such registration and any transfer taxes or underwriting discounts,
commissions or fees applicable to the Registrable Securities sold by the Holder
pursuant thereto.

     The Company will take all actions which may be required to qualify or
register the Registrable Securities included in the Registration Statement for
the offer and sale under the securities or blue sky laws of such states as are
reasonably requested by each Holder of such securities, provided that the
Company shall not be obligated to execute or file any general consent to service
of process or to qualify as a foreign corporation to do business under the laws
of any such jurisdiction.


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     4.     ADDITIONAL TERMS.

            The Company shall indemnify and hold harmless the Holders and each
underwriter, within the meaning of the Securities Act, who may purchase from or
sell for any Holder, any Registrable Securities, from and against any and all
losses, claims, damages and liabilities caused by any untrue statement of a
material fact contained in the Registration Statement, any other registration
statement filed by the Company under the Securities Act with respect to the
registration of the Registrable Securities, any post-effective amendment to such
registration statements, or any prospectus included therein or caused by any
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, except insofar as such
losses, claims, damages or liabilities are caused by any such untrue statement
or omission based upon information furnished or required to be furnished in
writing to the Company by the Holders or underwriter expressly for use therein,
which indemnification shall include each person, if any, who controls any Holder
or underwriter within the meaning of the Securities Act and each officer,
director, employee and agent of each Holder and underwriter; provided, however,
that the indemnification in this Section 4(a) with respect to any prospectus
shall not inure to the benefit of any Holder or underwriter (or to the benefit
of any person controlling any Holder or underwriter) on account of any such
loss, claim, damage or liability arising from the sale of Registrable Securities
by the Holder or underwriter, if a copy of a subsequent prospectus correcting
the untrue statement or omission in such earlier prospectus was provided to such
Holder or underwriter by the Company prior to the subject sale and the
subsequent prospectus was not delivered or sent by the Holder or underwriter to
the purchaser prior to such sale and provided further, that the Company shall
not be obligated to so indemnify any Holder or any such underwriter or other
person referred to above unless the Holder or underwriter or other person, as
the case may be, shall at the same time indemnify the Company, its directors,
each officer signing the Registration Statement and each person, if any, who
controls the Company within the meaning of the Securities Act, from and against
any and all losses, claims, damages and liabilities caused by any untrue
statement of a material fact contained in the Registration Statement, any
registration statement or any prospectus required to be filed or furnished by
reason of this Agreement or caused by any omission to state therein a material
fact required to be stated therein or necessary to make the statements therein
not misleading, insofar as such losses, claims, damages or liabilities are
caused by any untrue statement or omission based upon information furnished in
writing to the Company by the Holder or underwriter expressly for use therein.

            If for any reason the indemnification provided for in the preceding
section is held by a court of competent jurisdiction to be unavailable to an
indemnified party with respect to any loss, claim, damage, liability or expense
referred to therein, then the indemnifying party, in lieu of indemnifying such
indemnified party thereunder, shall contribute to the amount paid or payable by
the indemnified party as a result of such loss, claim, damage or liability in
such proportion as is appropriate to reflect the relative fault of the
indemnified party and the indemnifying party, as well as any other relevant
equitable considerations.

            Neither the filing of a Registration Statement by the Company
pursuant to this Agreement nor the making of any request for prospectuses by the
Holder shall impose upon any Holder any obligation to sell the Holder's
Registrable Securities.


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            Each Holder, upon receipt of notice from the Company that an event
has occurred which requires a Post-Effective Amendment to the Registration
Statement or a supplement to the prospectus included therein, shall promptly
discontinue the sale of Registrable Securities until the Holder receives a copy
of a supplemented or amended prospectus from the Company, which the Company
shall provide as soon as practicable after such notice.

            If the Company fails to keep the Registration Statement referred to
above continuously effective during the requisite period, then the Company
shall, promptly upon the request of any Holder, use best efforts to update the
Registration Statement or file a new registration statement covering the
Registrable Securities remaining unsold, subject to the terms and provisions
hereof.

            Each Holder agrees to provide the Company with any information or
undertakings reasonably requested by the Company in order for the Company to
include any appropriate information concerning the Holder in the Registration
Statement or in order to promote compliance by the Company or the Holder with
the Securities Act.

            (g)  The Company agrees that it shall cause each of its directors,
officers and shareholders owning ten percent (10%) or more of the Company's
outstanding Common Stock to refrain from selling any shares of the Company's
Common Stock until the Registration Statement has been declared effective.

            (h)  Each Holder, on behalf of itself and its affiliates, hereby
covenants and agrees not to, directly or indirectly, offer to "short sell",
contract to "short sell" or otherwise "short sell" any securities of the
Company, including, without limitation, shares of Common Stock that will be
received as a result of the conversion of the Series A Stock or the exercise of
the Warrants.

      5.    GOVERNING LAW. The Registrable Securities will be, if and when
            issued, delivered in California. This Agreement shall be deemed to
            have been made and delivered in the State of California and shall be
            governed as to validity, interpretation, construction, effect and in
            all other respects by the internal substantive laws of the State of
            California, without giving effect to the choice of law rules
            thereof.

      6.    AMENDMENT.  This Agreement may only be amended by a written
            instrument executed by the Company and the Holders.

      7.    ENTIRE AGREEMENT.  This Agreement constitutes the entire agreement
            of the parties hereto with respect to the subject matter hereof, and
            supersedes all prior agreements and understandings of the parties,
            oral and written, with respect to the subject matter hereof.

      8.    EXECUTION IN COUNTERPARTS.  This Agreement may be executed in one
            or more counterparts, each of which shall be deemed an original, but
            all of which together shall constitute one and the same document.


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      9.    NOTICES.  All communications hereunder shall be in writing and
            shall be hand delivered, mailed by first-class mail, couriered by
            next-day air courier or by facsimile  at the addresses set forth
            below.

               If to the Holders,   Mercator Advisory Group, LLC
                                    Mercator Momentum Fund, L.P.
                                    Mercator Momentum Fund III, L.P.
                                    Monarch Pointe Fund, Ltd.
                                    555 South Flower Street, Suite 4500
                                    Los Angeles, CA  90071
                                    Attention: David Firestone

               With a copy to Sheppard Mullin Richter & Hampton LLP
                                    333 South Hope Street
                                    48th Floor
                                    Los Angeles, CA 90071-1448
                                    Telephone No.: (213) 620-1780
                                    Facsimile No.:  (213) 620-1398
                                    Attention:     David C. Ulich

               If to the Company,   Medical Discoveries, Inc.
                                    738 Aspenwood Lane
                                    Twin Falls, Idaho 83301
                                    Telephone No.: (208) 736-1799
                                    Facsimile No.: (208) 733-5877
                                    Attention:  Judy M. Robinett


With a copy to                      Stoel Rives LLP
                                    101 S. Capitol Blvd., Suite 1900
                                    Boise, Idaho 83702
                                    Telephone No.: (208) 389-9000
                                    Facsimile No.:  (208) 389-9040
                                    Attention:     Stephen R. Drake

All such notices and communications shall be deemed to have been duly given: (i)
when delivered by hand, if personally delivered; (ii) five business days after
being deposited in the mail, postage prepaid, if mailed certified mail, return
receipt requested; (iii) one business day after being timely delivered to a
next-day air courier guaranteeing overnight delivery; (iv) the date of
transmission if sent via facsimile to the facsimile number as set forth in this
Section or the signature page hereof prior to 4:00 p.m. on a business day, or
(v) the business day following the date of transmission if sent via facsimile at
a facsimile number set forth in this Section or on the signature page hereof
after 4:00 p.m. or on a date that is not a business day. Change of a party's
address or facsimile number may be designated hereunder by giving notice to all
of the other parties hereto in accordance with this Section.


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      10.     BINDING EFFECT; BENEFITS. Any Holder may assign its rights
            hereunder. This Agreement shall inure to the benefit of, and be
            binding upon, the parties hereto and their respective heirs, legal
            representatives, successors and assigns. Nothing herein contained,
            express or implied, is intended to confer upon any person other than
            the parties hereto and their respective heirs, legal representatives
            and successors, any rights or remedies under or by reason of this
            Agreement.

      11.     HEADINGS.  The headings contained herein are for the sole purpose
            of convenience of reference, and shall not in any way limit or
            affect the meaning or interpretation of any of the terms or
            provisions of this Agreement.

      12.     SEVERABILITY. Any provision of this Agreement which is held by
            a court of competent jurisdiction to be prohibited or unenforceable
            in any jurisdiction(s) shall be, as to such jurisdiction(s),
            ineffective to the extent of such prohibition or unenforceability
            without invalidating the remaining provisions of this Agreement or
            affecting the validity or enforceability of such provision in any
            other jurisdiction.

      13.     JURISDICTION.  Each of the parties irrevocably agrees that any and
            all suits or proceedings based on or arising under this Agreement
            may be brought only in and shall be resolved in the federal or state
            courts located in the City of Los Angeles, California and consents
            to the jurisdiction of such courts for such purpose. Each of the
            parties irrevocably waives the defense of an inconvenient forum to
            the maintenance of such suit or proceeding in any such court. Each
            of the parties further agrees that service of process upon such
            party mailed by first class mail to the address set forth in Section
            9 shall be deemed in every respect effective service of process upon
            such party in any such suit or proceeding. Nothing herein shall
            affect the right of either party to serve process in any other
            manner permitted by law. Each of the parties agrees that a final
            non-appealable judgment in any such suit or proceeding shall be
            conclusive and may be enforced in other jurisdictions by suit on
            such judgment or in any other lawful manner.

      14.     ATTORNEYS' FEES AND DISBURSEMENTS. If any action at law or in
            equity is necessary to enforce or interpret the terms of this
            Agreement, the prevailing party or parties shall be entitled to
            receive from the other party or parties reasonable attorneys' fees
            and disbursements in addition to any other relief to which the
            prevailing party or parties may be entitled.

            [The balance of this page is intentionally left blank.]



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        IN WITNESS WHEREOF, this Agreement has been executed and delivered by
the parties hereto as of the date first above written.

                            MEDICAL DISCOVERIES, INC.


                            By:_________________________________
                            Name: Judy M. Robinett
                            Its: President & CEO

                            HOLDERS:


                            MERCATOR MOMENTUM FUND, LP


                            By: Mercator Advisory Group, LLC
                            Its: General Partner

                            By:_________________________________
                            Name: David Firestone
                            Its: Managing Member

                            MERCATOR MOMENTUM FUND III, LP

                            By: Mercator Advisory Group, LLC
                            Its: General Partner

                            By:_________________________________
                            Name: David Firestone
                            Its: Managing Member

                            MERCATOR ADVISORY GROUP, LLC

                            By:_________________________________
                            Name: David Firestone
                            Its: Managing Member