Background: Topical corticoids decrease de novo collagen synthesis in the human skin. Objective: We studied the effect of three corticoids, hydrocortisone (HC), methylprednisolone aceponate (MPA) and momethasone furoate (MMF) on the de novo synthesis of type I and III collagens. Methods: Fifteen healthy male volunteers treated four areas marked on their abdominal skin for 1 week. HC was applied twice a day, MPA and MMF once a day plus vehicle once a day and vehicle twice a day. After the treatment, suction blisters were induced on the treated areas, the suction blister fluid (SBF) was collected and procollagen propeptides of type I and III procollagens (PINP, PIIINP, respectively) were analyzed by radioimmunological assays. The protein concentration in SBF was determined by a colorimetric method. Results: All the corticoids studied decreased the procollagen propeptide concentrations in SBF. HC decreased PINP concentration by 66%, MPA by 68% and MMF by 72%. HC decreased PIIINP by 62%, MPA by 68% and MMF by 72%. The protein concentration in SBF was decreased by 11-15% by these topical corticoids. Conclusion: HC decreases the concentration of procollagen propeptides in human skin in males to nearly the same extent as MPA and MMF.