Pirprofen is a non-steroidal anti-inflammatory drug, related structurally to drugs such as ibuprofen, ketoprofen and naproxen. Published clinical trials indicate that pirprofen 600 to 1200 mg/day as 2 or 3 divided doses is a suitable alternative to usual therapeutic dosages of aspirin, flurbiprofen, ibuprofen, indomethacin, ketoprofen, naproxen, piroxicam and sulindac in the treatment of rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, musculoskeletal disorders and non-articular rheumatism. More studies are required to evaluate its potential relative to other commonly used drugs in the treatment of gout, juvenile rheumatoid arthritis and dysmenorrhoea. In patients with acute postsurgical, trauma or cancer pain, single oral or intramuscular doses of pirprofen 200 to 400mg provide equivalent analgesic activity to usual therapeutic doses of aspirin, diflunisal, ketoprofen, noramidopyrine, paracetamol and pentazocine. As with other non-steroidal anti-inflammatory drugs, gastrointestinal complaints are the most frequently reported side effects. At equivalent analgesic or anti-inflammatory dosages, pirprofen probably causes fewer side effects than aspirin and appears to be as well tolerated as the other agents with which it has been compared. Long term tolerability, particularly compared with some of the newer, purportedly less gastrotoxic agents or formulations, needs to be investigated further. Pirprofen does not appear likely to offer any particular advantage with respect to efficacy and tolerability over other non-steroidal anti-inflammatory drugs, except aspirin. However, as no one agent is the most suitable drug for all patients requiring such therapy, pirprofen may be considered along with other drugs of this type in the therapy of arthritic conditions and acute pain states.