This study sought to investigate the effect of 3-week therapy with sulphur baths on antioxidative defence systems, peroxide concentrations, and lipid levels in patients with degenerative osteoarthritis. After randomisation, one group of patients (n = 19) received sulphur baths during their stay at a health resort (sulphur group) whereas the other patient group served as controls (n = 19, control group). Total cholesterol levels, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides and the antioxidative status, glutathione peroxidase and superoxide dismutase (SOD) activities, and peroxide concentration as an oxidative stress parameter, were evaluated at the start and end of therapy. A non-significant decline in peroxide concentrations and significant lower SOD activities were detected in the sulphur group at the end of the therapy. Until the end of therapy, total cholesterol levels changed differentially in the sulphur group (from 229.11 ± 34.47 mg/dl to 217.46 ± 40.45 mg/dl) and in the control group (from 197.63 ± 34.66 mg/dl to 207.95 ± 33.02 mg/dl). A similar significant group difference was found for LDL, with a 5.9% reduction in the sulphur group and a 6.1% increase in the control group. Triglyceride concentrations were non-significantly reduced in both groups after 3 weeks at the health resort (sulphur group 11.2%, control group 20.2%). The HDL values changed only minimally in both groups.