Abstract: Use of a compound of formula (I) or a 3-enol C1-4 alkanoate ester thereof in the manufacture of a medicament for the intermittent treatment of a condition of a human or non-human mammal in which said mammal has an abnormally high serum concentration of an adrenal hormone: Wherein R1, R2, R5, and R6 are the same or different and each is hydrogen or C1 to 4? alkyl; R3 is hydrogen C1 to 4? alkyl, C1 to 4? alkenyl or C1 to 4? alkynyl; R4 is hydroxy, C1 to 4? alkanoyloxy, a group of formula (II) or (III) Wherein R7 is (CH2)n, where n is an integer of from 0 to 4, R8 is hydrogen, C1 to 4? alkyl, hydroxy or NH2 and R9 and R10 are the same or different and each is hydrogen or C1 to 4? Alkyl; or R3 and R4 together are oxo, ethylenedioxy or propylenedioxy. The invention has practical benefits for the treatment of man and other animals with diseases associated with abnormal production of adrenal steroids.