Diflunisal is a salicylic acid derivative with analgesic and anti-inflammatory activity. It was developed by Merck Sharp & Dohme in 1971, after showing promise in a research project studying more potent chemical analogs of aspirin. It was first sold under the brand name Dolobid, by Merck & Co., but generic versions are widely available. It is classed as a nonsteroidal anti-inflammatory drug (NSAID) and is available in 250 mg and 500 mg tablets.