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                                                                     EXHIBIT 4.2

                                  AMENDMENT TO
            CERTIFICATE OF DESIGNATION OF PREFERENCES AND RIGHTS OF
                      SERIES A CONVERTIBLE PREFERRED STOCK
                                       OF
                            MEDIAL DISCOVERIES, INC.
                               a Utah corporation

         The undersigned, Judy M. Robinett and Stephen R. Drake certify that:

                  1.    They are the duly acting President & CEO and Secretary,
         respectively, of Medical Discoveries, Inc. a corporation organized and
         existing under the laws of the State of Utah (the "CORPORATION").

Pursuant to authority conferred upon the Board of Directors by the Certificate
of Incorporation of the Corporation, and pursuant to the provisions of
Corporations Code of the State of Utah, said Board of Directors, pursuant to a
meeting held on November 30, 2004, adopted a resolution amending the Certificate
of Designations of Preferences and Rights of the Corporation's Series A
Convertible Preferred Stock, as follows:

                  1.    Section (b) Authorized Shares is deleted in its entirety
and the following is inserted: "(b) Authorized Shares. The number of authorized
shares constituting the Series A Preferred Stock shall be forty-two thousand
(42,000) shares of such series."

                  2.    Section (f)(iii) Conversion Price is deleted in its
entirety and the following is inserted: "(f)(iii) Conversion Price. The number
of shares into which one share of Series A Preferred Stock shall be convertible
shall be determined by dividing the Series A Purchase Price by the then
existing Conversion Price (as set forth below) (the "CONVERSION RATIO"). The
"CONVERSION PRICE" per share for the Series A Preferred Stock shall be equal to
eighty-five percent (85%) of the Market Price (as defined below and subject to
adjustment as described below), rounded to the nearest ten thousandth;
provided, however, that subject to the provisions of the next sentence, in no
event shall the Conversion Price exceed $0.1967 (the "CEILING PRICE"). The
Ceiling Price shall be further adjusted upon the occurrence of any event in
paragraph (f)(i-v)-(vi)."

                  3.    All references to Floor Price are hereby deleted.

                  4.    In all other respects the Certificate of Designations
shall remain unchanged and in full force and effect.

                  5.    The undersigned represent and warrant that approval of
the shareholders of Medical Discoveries, Inc., is not required for this
Amendment.

Each of the undersigned declares under penalty of perjury that the matters set
out in the foregoing Certificate are true of his own knowledge. Executed at
_____, _____, on this __ day of December, 2004.

                            Signature Page to Follow

                                      -1-

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                                             /s/ Judy M. Robinett
                                             --------------------------------
                                             Name:  Judy M. Robinett
                                             Title: President & CEO

                                             /s/ Stephen R. Drake
                                             --------------------------------
                                             Name:  Stephen R. Drake
                                             Title: Secretary

                                      -2-<PAGE>

                                                                     EXHIBIT 4.3

                          REGISTRATION RIGHTS AGREEMENT

      AGREEMENT dated as of October 18, 2004, between MONARCH POINTE FUND, LTD.
(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 $1,200,000, an
aggregate of 12,000 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 4,575,496 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.

           (a)   The Company shall file a registration statement (the
"Registration Statement") with the Securities and Exchange Commission (the
"SEC") within thirty (30) days after the date of this Agreement 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 (i) the date that all of
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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.

         (b)   The Company will initially include in the Registration Statement
as Registrable Securities Twenty-Four Million (24,000,000) 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:

         (a)   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.

         (b)   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.

         (c)   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.

         (a)   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.

         (b)   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

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            relative fault of the indemnified party and the indemnifying party,
            as well as any other relevant equitable considerations.

      (c)   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.

      (d)   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.

      (e)   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.

      (f)   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

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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.

   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

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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.

   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.

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             [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: /s/ Judy M. Robinett
                                          ------------------------
                                      Name: Judy M. Robinett
                                      Its:  President & CEO

                                      HOLDERS:

                                      MONARCH POINTE FUND, LTD.

                                      By: /s/ Harry Aharonian
                                          ------------------------
                                      Name: Harry Aharonian
                                      Its:  Director

                                      MERCATOR ADVISORY GROUP, LLC

                                      By: /s/ Harry Aharonian
                                          ------------------------
                                      Name: Harry Aharonian
                                      Its:  Portfolio Manager

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