In. 3 normal cats repeated blood determinations made without excitation during 2 wks. showed a fairly constant blood cholesterol level. In 10 experiments, excitation of 8 normal cats produced an emotional hypercholesterolemia, which in 8 experiments was followed by permanent return to normal; in 2 experiments (on the same cat) a transient depression followed the rise of cholesterol level. In 2 sympathectomized cats no emotional hypercholesterolemia followed excitation. Emotional hypercholesterolemia was somewhat increased in a cat following cholecystectomy.