Ten investigators in Austria, Belgium, Denmark, Germany and Switzerland participated in an open trial of intramuscular piroxicam involving 135 patients with selected acute sprains, tendinitis or low back pain. The drug was given in the recommended regimen of 40 mg once daily for 2 days and 20 mg once daily thereafter. Statistically significant improvement from baseline in pain was evident within 1 hour of the initial dose, an effect which was enhanced over a 12-hour period and which lasted for 24 hours. After 3 days of intramuscular injections, pain, tenderness, morning stiffness and back elongation were markedly improved. Subsequent treatment with either intramuscular or oral piroxicam further improved these symptoms and most patients recovered their normal physical activity within a week. The drug was well tolerated; twenty-five patients (18·5%) reported side-effects possibly related to piroxicam. Nearly all were mild or moderate in severity with only six resulting in disruption of therapy. Most adverse reactions involved the upper gastrointestinal tract, but there were no reports of gastric bleeding. Except for a few patients with injection site pain, the side-effect profile was similar to that established with the oral dosage form. Toleration was regarded as excellent or good in about 84% of the patients. The results indicate that intramuscular piroxicam can provide rapid and effective therapy with good toleration in the treatment of acute musculoskeletal disorders.