EXHIBIT 23.1
 
               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
    We consent to the incorporation by reference in this Annual Report (Form
10-K) of Cygnus, Inc. of our report dated January 20, 1997, included in the 1996
Annual Report to Stockholders of Cygnus, Inc.
 
    Our audits also included the financial statement schedule of Cygnus, Inc.
listed in Item 14(a). This schedule is the responsibility of the Company's
management. Our responsibility is to express an opinion based on our audits. In
our opinion, the financial statement schedule referred to above, when considered
in relation to the basic financial statements taken as a whole, presents fairly
in all material respects the information set forth therein.
 
    We consent to the incorporation by reference in the Registration Statements
(Form S-8 Nos. 33-41502, 33-43710, 33-59774, 33-86038 and 333-18357) pertaining
to the Amended 1986 Stock Option Plan, the 1991 Amended Employee Stock Purchase
Plan, the Amended 1986 Incentive Stock Plan and the 1994 Stock Option/Award Plan
of Cygnus, Inc. of our report dated January 20, 1997, with respect to the
consolidated financial statements and schedule of Cygnus, Inc. included or
incorporated by reference in the Annual Report (Form 10-K) for the year ended
December 31, 1996.
 
                                          /s/ ERNST & YOUNG LLP
 
Palo Alto, California
March 20, 1997
 
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