The disease RA itself is assumed to be a risk factor for the occurrence of adverse drug reactions during sulphasalazine therapy. A meta-analysis comparing treatment termination because of toxicity among RA, inflammatory bowel disease and seronegative spondylarthropathy patients was conducted. It is shown that RA itself does not appear to predispose to treatment discontinuation because of adverse reactions. Differences found in the incidence of side effects among the various disease groups can probably be explained by patient selection, particularly with respect to age, proportion treated for the first time with sulphasalazine, and dosage used. The side effect profiles in the three groups studied are not different. However, a trend towards greater haematological and hepatic toxicity in rheumatic patients is noticed.