[EPSTEIN, BECKER & GREEN, P.C. LETTERHEAD]



                                                                     Exhibit 5.1


May 24, 2006


The Board of Directors
Medical Discoveries, Inc.
1338 S. Foothill Drive, #266
Salt Lake City, UT 84108

We have acted as counsel for Medical Discoveries, Inc., a Utah corporation (the
"Company"), in connection with the Registration Statement on Form SB-2,
Registration No. 333-121635 (the "Registration Statement") filed by the Company
with the Securities and Exchange Commission under the Securities Act of 1933, as
amended (the "Act"), relating to the resale by selling shareholders of up to
113,511,158 shares of Common Stock, without par value of the Company (the
"Shares").

We have reviewed the corporate action of the Company in connection with this
matter and have examined the documents, corporate records, and other instruments
we deemed necessary for the purposes of this opinion.

In rendering this opinion, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, and the
conformity to authentic original documents of all documents submitted to us as
copies.

Based upon the foregoing, it is our opinion that the Shares, when issued,
delivered and sold in the manner described in the Registration Statement, will
be validly issued, fully paid and nonassessable.

We do not express any opinions in this letter concerning any law other than the
laws of the state of Utah and the federal laws of the United States of America.

This opinion is furnished solely for the benefit of the Company and may not be
filed with or furnished to any individual, entity, association, agency or other
person and may not be quoted or referred to, orally or in writing, in whole or
in part, without our prior written consent. We hereby consent to the filing of
this opinion as an exhibit to the Registration Statement and to the reference to
our firm in the prospectus constituting a part thereof. In giving such consent,
we do not thereby admit that we are in the category of persons whose consents
are required under Section 7 of the Act.

Very truly yours,

/s/ EPSTEIN, BECKER & GREEN, P.C.
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EPSTEIN, BECKER & GREEN, P.C.