The authors studied the effect of oyster fungus (Pleurotus ostreatus) (2% dried fruiting bodies in a standard diet) on the serum and liver lipids of growing male Syrian hamsters with a chronic alcohol intake (a 15% aqueous solution). After eight weeks' alcohol intake there was an increase in their serum cholesterol, triacylglycerol (TG) and phospholipid (PL) concentration, 40 - 60% of which was accounted for by an increase in the very low density lipoprotein (VLDL) concentration. The proportion of VLDL in the lipoprotein pool rose by almost 15%, whereas the proportion of high density lipoproteins (HDL) fell. The simultaneous administration of the fungus in the diet reduced the cholesterol level below the value in the control animals not given any alcohol. Both the serum TG and the VLDL concentration fell by 30%, but neither the chemical composition and concentration of the HDL nor the cholesterol concentration were affected. The addition of the fungus to the diet completely abolished the increase induced in the liver cholesterol and TG concentration by the chronic intake of alcohol.