EXHIBIT 5.1

                                            July 2, 2001



Genelabs Technologies, Inc.
505 Penobscot Drive
Redwood City, California  94063

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

               We have acted as special counsel to Genelabs Technologies,
Inc., a California corporation (the "Company"), in connection with the
registration of: (i) 2,000,000 shares of the Company's common stock, no par
value ("Common Stock"), issuable pursuant to an amendment to the Company's
2001 Employee Stock Purchase Plan (the "ESPP"); and (ii) 2,500,000 shares
of Common Stock issuable pursuant to an amendment to the Company's 2001
Stock Option Plan (the "SOP" and, together with the ESPP, the "Plans"). The
4,500,000 shares of Common Stock to be registered pursuant to the Plans, in
aggregate, are collectively referred to herein as the "Shares."

               This opinion is being furnished in accordance with the
requirements of Item 601(b)(5) of Regulation S-K under the Securities Act
of 1933, as amended (the "Securities Act").

               In connection with this opinion, we have examined originals
or copies, certified or otherwise identified to our satisfaction, of: (i)
the Company's Registration Statement on Form S-8, relating to the Shares,
filed with the Securities and Exchange Commission (the "Commission") on or
around July 2, 2001 under the Securities Act (together with all exhibits
thereto, the "Registration Statement"); (ii) the Amended and Restated
Articles of Incorporation of the Company, as currently in effect, (iii) the
Bylaws of the Company, as currently in effect, (iv) a specimen certificate
representing Common Stock (the "Form of Common Stock Certificate"); (v) the
Plans; (vi) certain resolutions of the Board of Directors of the Company
relating to the issuance and sale of the Shares and related matters; and
(vi) the form of option agreement to be entered into between the Company
and each of the employees, directors, officers, advisors and consultants
receiving options under the Plans (the "Form of Option Agreement"). We have
also examined originals or copies, certified or otherwise identified to our
satisfaction, of such records of the Company and such agreements,
certificates of officers or other representatives of the Company and
others, and such other documents, certificates and records as we have
deemed necessary or appropriate as a basis for the opinions set forth
herein.

               In our examination, we have assumed the legal capacity of
all natural persons, the genuineness of all signatures, the authenticity of
all documents submitted to us as originals, the conformity to original
documents of all documents submitted to us as certified or photostatic
copies and the authenticity of the originals of such latter documents. In
making our examination of documents executed or to be executed by parties
other than the Company, we have assumed that such parties had the power,
corporate or other, to enter into and perform all obligations thereunder
and have also assumed the due authorization by all requisite action,
corporate or other, and execution and delivery by such parties of such
documents and the validity and binding effect thereof. We have further
assumed that any agreements that will be entered into between the Company
and each of the employees, directors, officers, advisors and consultants
receiving options under the Plans will conform to the Form of Option
Agreement. As to any facts material to the opinions expressed herein which
we have not independently established or verified, we have relied upon oral
or written statements and representations of officers and other
representatives of the Company and others.

               We express no opinion as to any laws other than the
California General Corporation Law.

               Based upon and subject to the foregoing, we are of the
opinion that the Shares to be issued under the Plans have been duly
authorized for issuance and, when the Shares have been issued, delivered
and paid for in accordance with the terms and conditions of the Plans and
the Form of Option Agreement, and the Form of Common Stock Certificate has
been manually signed by an authorized officer of the transfer agent and
registrar for the Shares and registered by such transfer agent and
registrar, such Shares will be validly issued, fully paid and
nonassessable.

               We hereby consent to the filing of this opinion with the
Commission as Exhibit 5.1 to the Registration Statement. In giving such
consent, we do not thereby admit that we are included in the category of
persons whose consent is required under Section 7 of the Securities Act or
the rules and regulations of the Commission.


                             Very truly yours,


                             /s/ Skadden, Arps, Slate, Meagher & Flom LLP