<;P>;PROBLEM TO BE SOLVED: To provide a collagen synthesis promotor containing glycylproline of a dipeptide of glycine and proline, a skin external preparation, and a drug composition. <;P>;SOLUTION: Glycylproline of a dipeptide of glycine and proline includes an effect of promoting the synthesis of collagen which decreases with ageing or diseases. Particularly, the glycylproline promotes the synthesis of type 12 collagen and is effective as a drug composition for preventing or improving skin ageing or ophthalmic diseases in which type 12 collagen participates. <;P>;COPYRIGHT: (C)2011,JPO&INPIT