Thirty-nine nitrogen-containing steroids were tested against two gram-negative, five gram-positive, and two yeast organisms. Many of these steroids have been previously reported to inhibit various metabolic processes involving sterol metabolism. While low minimal inhibitory concentration (MIC) values were recorded for sterol producing yeast, growth of bacteria which contain no sterols was also inhibited. Structure-function studies provided no relationship between biological activity and hypocholesteremic effects of these azasteroids. A hypothesis put forward is that amino and azasteroids are effectors of membrane which, in the case of mitochondria, lead to changes in adenosine triphosphate levels and/or dehydrogenase activity. Their effects on sterol metabolism, therefore, may be of secondary consideration.