Dimethyl sulfoxide (DMSO) is an inorganic compound with many interesting in vitro properties, including the ability to scavenge oxygen-free radicals. DMSO has been used to treat a variety of clinical conditions, especially musculoskeletal trauma, but valid data regarding its effectiveness are lacking. This paper reviews the pharmacology of DMSO and reports on its effectiveness in reducing posttraumatic limb swelling and ankle joint stiffness in a rabbit hind limb model. The left and right hind limbs of the test and control animals were instrumented and fractured identically. DMSO was applied daily to the skin of only one limb in the test animals. DMSO reduced postinjury ankle stiffness in both ankles of the test rabbits by 41% but had no effect on limb swelling compared to control rabbits. Postulated mechanisms of decreased joint stiffness include oxygen-free radical scavenging and inhibition of fibroblast proliferation.