Zidometacin is a nonsteroidal anti-inflammatory agent structurally related to indomethacin that has been studied for osteoarthritis treatment. Pharmacological studies show its favorable activity/ulcerogenicity ratio in comparison to indomethacin. Preliminary clinical data indicate a good analgesic effect after a single dose and an improvement of functional conditions of the joint after short-term therapy. Zidometacin either as capsules or as suppositories showed a statistically significant influence on pain and functional indices in osteoarthritis patients. The side-effects reported by patients were dizziness and nausea with capsules and anal burning with suppositories.