Mesalamine is a monohydroxybenzoic acid that is salicylic acid substituted by an amino group at the 5-position. It has a role as a non-steroidal anti-inflammatory drug. It is an aromatic amine, an amino acid, a member of phenols, a monocarboxylic acid and a monohydroxybenzoic acid. It is functionally related to a salicylic acid. It is a conjugate acid of a mesalaminate(1-).

   5-Aminosalicylic acid is used in the preparation of gastrointestinal anti-inflammatory agents. It is a metabolite of sulfasalazine. It acts as a drug involved in the treatment of Crohn's disease and ulcerative colitis. Further, it is used to make dyes and light-sensitive papers.