Although plasma lipid levels are assumed to reflect the individual's constitutional or nutritional status, many studies have found that plasma lipids are noticeably influenced by short-term emotional arousal. Sixty such studies are reviewed. These studies span a remarkable breadth of stressful situations, such as from viewing disturbing films to taking examinations or participating in military training courses. Free fatty acid levels were almost invariably elevated in the context of a stressful event. Most studies also found that cholesterol increased from 8 to 65% above baseline under stressful conditions. In some individuals cholesterol levels may be highly labile. There was no consistent pattern of triglyceride response to emotional arousal. This area, although imaginatively studied 20 years ago, has been relatively ignored in recent years. The availability of more sophisticated techniques for studying psychological stress, neuroendocrine response, and lipid metabolism makes this topic a fertile area for further study.