This article provides a background for the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in sports medicine, including the nature of the drugs, the settings and rationale for their use, and concerns about their general safety. The criteria for the ideal study to examine the efficacy and safety of NSAIDs after acute injury is then enumerated, including a review of how many of the published studies have met each of the major criteria. Selected studies are described to demonstrate those that have or have not provided the basis for a rational decision on the use of NSAIDs in sports medicine and in the treatment of tendinitis. Finally, this article draws conclusions based on these published studies.