A composition, a food or a drink which contains sea squirts or a processed product thereof as the active ingredient and is used for inhibiting the progress of muscular dystrophy symptoms or conditions relating thereto or ameliorating the same. The above-described composition, food or drink can be easily taken in the daily life and shows little side effects. It is also intended to provide a method of inhibiting the progress of muscular dystrophy symptoms or conditions relating thereto or ameliorating the same.
