Intradermal injections with suspension of hydrocortisone acetate microcrystals have been found1 to have a uniform definite local inhibition of the inflammatory process in psoriasis. The intradermal injection cleared up a small area around the hydrocortisone deposits—very few millimeters in diameter. After the disappearance of the crystals from the skin the psoriasis invariably recurred. The attempt to spread the deposit of crystalline material over wider areas was unsuccessful. The remarkable effect resulting from the use of triamcinolone in psoriatic arthritis2 influenced me to experiment with this drug. Intradermal injections of a suspension of triamcinolone diacetate microcrystals revealed that the ability to suppress the inflammation of psoriasis locally was identical with that of hydrocortisone. Also, the size of the clearing was not different. It further revealed that intradermal injections of triamcinolone is not superior to hydrocortisone, and has little value in the treatment of psoriasis. Besides the human skin, the