Forty-three out-patients received treatment (6 months in 13 cases of spondylarthrosis, 12 months in 30 cases of gonarthrosis) with heterologous antibodies to articular tissue, given as 1 rectal suppository once every other day for periods of 4 weeks out of every 5. The treatment produced complete freedom from symptoms and signs of the illness in 5 (12%) patients and overall positive therapeutic results in 36 (84%), equally distributed in the disorders of the vertebral column and of the knee. This was accompanied by a significant improvement, both in terms of percentage improvement and the percentage of patients improved, of all monitored symptoms. The percentage improvement was similar for all components of the illness: pain, mobility and inflammatory-reactive component. No local or systemic side-reactions were recorded throughout the observation period, and there were no adverse effects on haematology, haematochemistry or renal function. A high percentage of patients reported a remarkable improvement in their quality of life, an overall measure of the therapeutic benefit-risk ratio as experienced by the individual patient.