The authors summarize present-day knowledge about neurocirculatory asthenia. They cover definition of the disorder, its terminology, symptomatology and history, its high family prevalence, and its course and outcome. Special emphasis is given to clinical evidence of the relation of life situations to the disorder. Exacerbations frequently correspond in time with emotion-provoking situations. When subjected to various stressful situations, patients suffering from neurocirculatory asthenia show quantitative and objective abnormalities in pulse-rates, minute respiratory volumes, ventilatory efficiency, blood lactate concn., work performances, oxygen consumptions, wincing and withdrawal reactions. Some of the stresses and stimuli which bring about these atypical responses are: pain, cold, muscular effort, CO2 a sudden noise, or flash of light. There is as yet " no crucial or final evidence as to the cause of the disorder or its relationship to more complicated or natural life situations.".