A double-blind comparison of intra-articular Thio-tepa, Depo-medrol, and procaine was performed in thirty-nine patients with inflammatory arthritis. Thio-tepa demonstrated a slight superiority, but the potential adverse systemic effects of the drug may not warrant its use. However, no such effects were noted in this study despite a dose of sixty milligrams. Medical synovectomy was not a demonstrable result of this treatment.