Although clearly demonstrated in idiopathic thrombocytopenic purpura and Kawasaki disease, the efficacy of intravenous immunoglobulins in the treatment of rheumatic and connective tissue diseases remains to be confirmed in double-blind placebo-controlled studies. This article is a review of some rheumatic and connective tissue diseases (ie, rheumatoid arthritis, juvenile rheumatoid arthritis, Still's disease, systemic lupus erythematosus, dermatomyositis-polymyositis, and vasculitis) in which anecdotal open studies occasionally have shown impressive clinical and biologic results with good tolerance. Intravenous immunoglobulins contain idiotypic antibodies directed against pathologic autoantibodies and appear to be an interesting source of immunomodulating antibodies, which could be useful in the treatment of autoimmune diseases.