The effect of butyl-6 alpha-fluoro-11 beta-hydroxy-16 alpha-methyl-3,20-dioxo-1,4-pregnadien-21-oate (fluocortin butylester, Vaspit) administered intratracheally and of beclomethasone dipropionate given intratracheally or orally on the adrenal glands of beagle dogs was investigated. The adrenal function was evaluated using a standardized ACTH stimulation test including eosinophil counts 5 h after a single i.v. injection of 0.02mg (approximately 2 IU) ACTH/kg body weight were found as well as the histological and morphometrical examination of the adrenal cortex. The cortisol determination (with Clark's method) 1.5 h and eosinophil counts to be the optimum indices for the evaluation of adrenal function. Beclomethasone dipropionate given intratracheally at daily dose levels of 0.05; 0.1 and 0.5 mg/kg body weight lead to a dose dependent adrenal suppression on the basis of plasma cortisol concentration, eosinophil counts after ACTH stimulation and size of zona fasciculata and reticularis. A complete adrenal suppression was observed at the highest dose level of 0.5 mg/kg bw. Also the oral administration of 0.1 mg/kg bw./day of beclomethasone dipropionate had a definite adrenal suppressive effect comparable to that of 0.1 mg/kg bw. given intratracheally. However, intratracheal administration of fluocortin butylester even after a 320 times higher dose (2 X 8 mg/kg bw./day) had no suppressive effect on the adrenal gland of the beagle dog.