In the course of a double-blind randomized study lasting 1 year 19 patients suffering from ensured rheumatoid arthritis (ARA criteria) were treated with oral hydrolytic enzymes or oral gold salts. The effects of these therapies were examined in regard to changes in serum concentrations of circulating immune complexes (CIC) and the complement component iC3b. After 12 months treatment with oral enzymes we determined a therapeutically wanted significant decrease of CIC whereas CIC increased up to 6 months. The best but not significant result under therapy with oral gold salts concerning CIC was a decrease in 6 out of 9 patients after 9 months. The complement component iC3b diminished with either therapy during the first 6 months and increased afterwards. As well as the reduction of circulating immune complexes, the intensified inactivation of C3b into iC3b during the second half-year with both treatments indicates that there might be a slight improvement of the pathologically changed immunoreactions after 6 months only. Concerning the examined laboratory parameters, no significant difference was found between both therapies.