The role of various dietary constituents in the etiology of hyperlipidemia and cardiovascular disease is examined in light of currently available data from epidemiological and clinical studies. Recommendations regarding the dietary management of the hyperlipidemic patient at risk are presented and the advisability of generalized dietary guidelines for the public examined. The certainties, which are few, and the uncertainties, which are numerous, regarding the cause and effect relationship between diet, hyperlipidemia, and cardiovascular disease suggest that dietary intervention to treat the hyperlipidemic patient is a rational first step but that the generalization of this approach for the public may be premature.