EXHIBIT 23.1 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in Registration Statement Nos. 33-71276, 33-94370, 333-83089, 333-84183, 333-38094 and 333-108716 on Form S-8 and Registration Statement Nos. 33-49082, 33-76094, 333- 24549, 333-76641, 333-77925, 333-31442, 333-32776, 333-34958, 333-35934 and 333-107820 on Form S-3 of AVANIR Pharmaceuticals of our report dated December 19, 2003, appearing in this Annual Report on Form 10-K of AVANIR Pharmaceuticals for the year ended September 30, 2003. DELOITTE & TOUCHE LLP San Diego, California December 19, 2003