Nonsteroidal anti-inflammatory drugs (NSAIDs) are substances other than steroids that inhibit a component of the inflammatory cascade. This article is dedicated to those substances which specifically inhibit cyclooxygenase. NSAIDs are used extensively in the veterinary field. This article discusses their pharmacologic mechanism of action, indications, and toxicity. The two isoforms of cyclooxygenase (COX-1 and COX-2) are reviewed along with the newer NSAID which are more effective and less toxic due to more specific COX-2 inhibition. Specific effects on soft tissue, bone, cartilage, and synovium are summarized. Pain modulation is extensively reviewed as well as the antiendotoxic and antithrombotic uses.