Tocopherol -deficient diets containing 2% and 4% corn oil produced encephalomalacia in chicks. Combinstions of 8% coconut oil, lauric or myristic acids, or a fatty acid mixture like coconut oil with 2% corn oil, significantly increased the incidence of encephalomalacia, while mixtures of 6% linseed oil, cod liver oil, or oleic acid with 4% corn oil inhibited the symptoms, and combinations with olive oil, butter, fatty acids like butter, or palmitic and stearic acids with corn oil had no effect on the incidence. Dietary linoleic acid appears to be the primary component of the lipids used in producing chick encephalomalacia, but other fatty acids can increase or decrease this effect.