An investigation on the effects of acute (10 mg/kg) and chronic (10 mg/kg for 15 days) treatment with Δ9‐THC administration by the intraperitoneal route, on the cholesterol, cerebroside and individual phospholipid contents in microsomal, synaptosomal, mitochodrial and myelin fractions from adult rat brain, is reported. The drug has been found to affect the different subcellular membranous lipid and phospholipid components in a characteristic manner. Copyright © 1975, Wiley Blackwell. All rights reserved