Corni Fructus (shanzhuyu), one of the important crude drugs in the traditional Chinese medicine, was said to be the sarcocarp of Cornus officinalis SIEB. et ZUCC. from which the seed has been removed. Internal morphologies of the crude drug were observed by comparison with some developmental stages from the flower bud to the mature fruit. The result of the observation made it clear that this crude drug was matured tissue of hypanthium, and that the removed part was the true fruit whose pericarp had been transformed into stone cells. Corni Fructus (shanzhuyu), one of the important crude drugs in the traditional Chinese medicine, was said to be the sarcocarp of Cornus officinalis SIEB. et ZUCC. from which the seed has been removed. Internal morphologies of the crude drug were observed by comparison with some developmental stages from the flower bud to the mature fruit. The result of the observation made it clear that this crude drug was matured tissue of hypanthium, and that the removed part was the true fruit whose pericarp had been transformed into stone cells.