In a randomised, double-blind comparative study involving a total of 1,630 out-patients, tenoxicam (a new non-steroidal anti-inflammatory drug belonging to the oxicam group), piroxicam and diclofenac retard were tested for their efficacy and tolerability in the treatment of osteoarthritis (OA) and extra-articular rheumatism (EAR). Single doses of 20 mg tenoxicam, 20 mg piroxicam or 100 mg diclofenac sodium retard were administered daily. Tenoxicam was found to be as effective as piroxicam and diclofenac sodium retard in the treatment of degenerative and extra-articular rheumatic disorders of the musculo-skeletal system. When baseline values were compared with values obtained at all subsequent examinations, all evaluation parameters for all three substances showed improvement. In analyses of the frequency, degree of severity and type of undesired effects, tenoxicam proved to be superior to the reference drugs. This was particularly evident from an improved gastrointestinal and central nervous system (CNS) tolerance and a lower rate of withdrawal from treatment. Tenoxicam has a favourable risk/benefit ratio and can be recommended for the treatment of chronic pain due to inflammation resulting from degenerative and extra-articular rheumatic disorders of the musculoskeletal system.