Cell culture has been used for many years, mainly using transformed cells, but in some instances normal cells. Generally, the more unsaturated fatty acids were most efficient at limiting cell growth. These fatty acids were usually more efficient at cell growth limitation and cell killing when used with transformed cells, compared to normal controls. Different species of mammals exhibit different capability to metabolise fatty acids, especially polyunsaturated fatty acids. The enzymes for such metabolism are largely cytosolic and mitochondrial, and are not found in erythrocytes. We have maintained erythrocytes from three species (rat, human and cat) in culture and exposed them to mixtures of fatty acids mimicking the composition of seven dietary oils. The mixtures induced varying degrees of erythrocyte death, generally depending on the type and amount of polyunsaturated fatty acids present in, and the concentration of the mixtures. Comparing the three species, the rat cells were generally the most susceptible to the effects of the fatty acids, with either human or cat least susceptible depending on the specific fatty acid mixture. Erythrocytes cannot metabolise fatty acids and hence are not able to remove the mixture dosed, and any effects are most likely to relate to changes in the erythrocyte membrane phosphoglyceride bilayer structure.