Abstract: The present invention provides a composition for the inhibition of and promotion of recovery from muscular fatigue or muscular damage and diseases associated therewith, in particular, muscular fatigue or muscular damage caused by exercise stress and diseases associated therewith, and a composition for the prevention or treatment of myofibrosis during the restoration at the damaged part associated with or incidental to surgical injury or surgical procedure, which are characterized by comprising as an active ingredient N-(3,4-dimethoxy-cinnnamoyl)anthranilic acid (generic name: tranilast) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof, and a method for use thereof.