The hydrocortisone diethylaminoacetate ointment and the hydrocortisone ointment were supplied through the courtesy of Dr. M. Carlozzi, of Charles Pfizer&Company, Inc., Brooklyn.It is generally accepted that lipid-soluble substances penetrate the epidermis better than water-soluble substances.1Rothman2states that, despite extensive discussion of this point, it has not been established that absorption is a straight function of the distribution coefficient lipid solubility/water solubility. Consequently it was unexpected to find that an ointment containing 0.5% hydrocortisone diethylaminoacetate, which is a water-soluble and lipophobic ester of hydrocortisone, was the therapeutic equivalent clinically, on topical application, of a 1% hydrocortisone in the same base. The water solubility of hydrocortisone diethylaminoacetate is 11 mg. per cubic centimeter in contrast to that of hydrocortisone (0.28 mg cc.) and hydrocortisone acetate (0.01 mg cc.).One hundred fifty-four patients with conditions usually responsive to topical steroid