Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the reference to our firm under the caption “Experts” in Amendment No. 1 to the Registration Statement (Form S-3 No. 333-145009) and related Prospectus of La Jolla Pharmaceutical Company and to the incorporation by reference therein of our report dated March 7, 2007, with respect to the consolidated financial statements of La Jolla Pharmaceutical Company included in its Annual Report (Form 10-K) for the year ended December 31, 2006, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

San Diego, California
August 17, 2007