Results obtained with cebus monkeys indicate that dietary myristic (14:0) and palmitic (16:0) acids exert disparate effects on cholesterol metabolism, whereas the ability of linoleic acid (18:2) to decrease total plasma cholesterol displays an upper limit or threshold. Reanalysis of published data suggests a similar situation pertains in humans. In agreement with an earlier human study, 14:0 appears to be the principal saturated fatty acid that raises plasma cholesterol whereas 18:2 lowers it. Oleic acid (18:1) appears neutral. The effect of 16:0 may vary. In normocholesterolemic subjects consuming diets containing less than or equal to 300 mg/day of cholesterol, 16:0 appears to be without effect on plasma cholesterol. However, in hypercholesterolemic subjects (greater than 225 mg/dl) and especially those consuming diets providing cholesterol intakes of greater than or equal to 400 mg/day, dietary 16:0 may expand the plasma cholesterol pool.