Exhibit 5.1

                         [Dorsey & Whitney Letterhead]


                                                    May 24, 2002

Alfacell Corporation
225 Belleville Avenue

Bloomfield, New Jersey 07003

Re: Registration Statement on Form S-1

Ladies and Gentlemen:

      We have acted as counsel to Alfacell Corporation, a Delaware corporation
(the "Company"), in connection with the Registration Statement on Form S-1 (the
"Registration Statement") filed by the Company under the Securities Act of 1933,
as amended (the "Act"), relating to the registration of an aggregate of
3,077,276 shares of the Company's common stock, $.001 par value per share (the
"Common Stock"), consisting of: (i) 1,538,638 outstanding shares of Common Stock
(the "Outstanding Shares"), and (ii)1,538,638 shares of Common Stock issuable
upon the exercise of warrants (the "Warrants").

      As such counsel, we have participated in the preparation of the
Registration Statement and have examined originals or copies, certified or
otherwise identified to our satisfaction, of such documents, corporate records,
certificates of public officials and other instruments and have conducted such
other investigations of fact and law as we have deemed relevant and necessary to
form a basis for the opinions hereinafter expressed. In conducting such
examination, we have assumed (i) that all signatures are genuine, (ii) that all
documents and instruments submitted to us as copies conform with the originals,
and (iii) the due execution and delivery of all documents where due execution
and delivery are a prerequisite to the effectiveness thereof. As to any facts
material to this opinion, we have relied upon statements and representations of
officers and other representatives of the Company and certificates of public
officials and have not independently verified such facts.

      Based solely upon the foregoing, it is our opinion that: The Outstanding
Shares to be sold by the shareholders as described in the Registration Statement
have been validly issued and are fully paid and non-assessable. The shares of
Common Stock issuable upon the exercise of the Warrants have been duly
authorized and reserved and, when issued in


accordance with the respective terms of the Warrants against payment therefore,
will be validly issued, fully paid and non-assessable.

      Our opinion expressed above is limited to the laws of the General
Corporation Law of the State of Delaware and the federal laws of the United
States of America.

      We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement, and to the reference to our firm under the heading
"Legal Matters" in the Prospectus constituting part of the Registration
Statement relating to the registration of the Shares. In giving such consent, we
do not thereby admit that we are in the category of persons whose consent is
required under Section 7 of the Act.

                                                               Very truly yours,

                                                        /S/ Dorsey & Whitney LLP