Sixteen general practitioners conducted a multicentre double-blind clinical trial to compare oxamethacin (100 mg t.i.d.) with indomethacin (50 mg t.i.d.) for a maximum duration of 2 weeks. Each drug was administered to 339 patients suffering from various pathological conditions requiring a non steroidal anti-inflammatory drug. When focusing on patients without associated drug therapy, 126/250 patients (50%) presented a good response on inflammation under oxamethacin and 98/236 patients (42%) a good response under indomethacin (p < 10−2); 141/250 patients (56%) presented a good response on pain under oxamethacin and 117/236 (50%) under indomethacin (p<5.10−2). Side effects and complaints were reported by 34/250 patients (14%) under oxamethacin and by 67/236 (28%) under indomethacin (p < 5.10−5). Some patients stopped treatment because of side-effects: 14/250 (6%) under oxamethacin and 32/236 (14%) under indomethacin (p < 2.10−3).