The present invention relates to a composition for preventing and treating muscle diseases or improving muscular function, containing a Platycodon grandiflorum extract. More specifically, the present invention relates to: a pharmaceutical composition for preventing and treating muscle diseases, containing a Platycodon grandiflorum extract a food composition for preventing muscle diseases or improving muscular function or a cosmetic for improving muscular function. The Platycodon grandiflorum extract of the present invention increases muscle formation by inducing muscular protein synthesis and muscle cell differentiation. Therefore, the extract is a natural product so as to be used safely without side effects, thereby being usable as an active ingredient of a pharmaceutical, food, or cosmetic composition exhibiting an excellent effect in preventing and treating muscle diseases or improving muscular function.
