EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

     We consent to the incorporation by reference in the Registration Statements (Form S-8 Nos. 333-106060, 333-116233, 333-131248, 333-125427, 333-143677 and 333-151825 and Form S-3 Nos. 333-101499, 333-31142, 333-43066, 333-55370, 333-81432, 333-131246 and 333-145009) of La Jolla Pharmaceutical Company and in the related Prospectus of our reports dated March 27, 2009, with respect to the consolidated financial statements of La Jolla Pharmaceutical Company and the effectiveness of internal control over financial reporting of La Jolla Pharmaceutical Company, included in this Annual Report (Form 10-K) for the year ended December 31, 2008.

/s/ Ernst & Young LLP  

San Diego, California
March 27, 2009