EXHIBIT 5


                      [LETTERHEAD OF DORSEY & WHITNEY LLP]

                                February 18, 1999


LecTec Corporation
10701 Red Circle Drive
Minnetonka, Minnesota 55343

Ladies and Gentlemen:

         We have acted as counsel to LecTec Corporation, a Minnesota corporation
(the "Company"), in connection with a Registration Statement on Form S-8 (the
"Registration Statement") relating to the sale by the Company from time to time
of up to 200,000 shares of Common Stock, $.01 par value per share, of the
Company (the "Shares"), issuable pursuant to the Company's Employee Stock
Purchase Plan (the "Plan").

         We have examined such documents and have reviewed such questions of law
as we have considered necessary and appropriate for the purposes of the opinions
set forth below.

         In rendering our opinions, we have assumed the authenticity of all
documents submitted to us as originals, the genuineness of all signatures and
the conformity to authentic originals of all documents submitted to us as
copies. We have also assumed the legal capacity for all purposes relevant hereto
of all natural persons and, with respect to all parties to agreements or
instruments relevant hereto other than the Company, that such parties had the
requisite power and authority (corporate or otherwise) to execute, deliver and
perform such agreements or instruments, that such agreements or instruments have
been duly authorized by all requisite action (corporate or otherwise), executed
and delivered by such parties and that such agreements or instruments are the
valid, binding and enforceable obligations of such parties. As to questions of
fact material to our opinions, we have relied upon certificates of officers of
the Company and of public officials.

         Based on the foregoing, we are of the opinion that the Shares have been
duly authorized and, upon issuance, delivery and payment therefor in accordance
with the terms of the Plan, will be validly issued, fully paid and
nonassessable.

         Our opinions expressed above are limited to the laws of the State of
Minnesota.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.


                                         Very truly yours,


                                         /s/ Dorsey & Whitney LLP

TSH