Urinary metabolites of glucocorticoids have been measured in man before and after administration of panthenol in high doses. The quantitative assay was performed according to the technique of Porter and Silber which measures only cortisol and some of its metabolites. In all panthenol treated subjects a significant increase in the urinary excretion of 17-alpha-21-dihydroxy-20-keto steroids has been observed and it appeared to be higher in male ageing between 18 and 25. The results obtained confirm that a statistically significant increase in glucocorticoid production after panthenol administration in high doses is present also in man.