Although ideas about stress and stress diseases have not yet crystallized, the current trend is to recognize stress as an important contributory cause of disease. There are many kinds of stress, and the ways in which they cause disease are not well understood. The problem is nevertheless real, and most authorities would include duodenal ulcer, thyrotoxicosis, malignant hypertension, thromboangiitis obliterans, ulcerative colitis, rheumatoid arthritis, and the collagen diseases in a list of diseases in which stress plays an important, if ill-defined role. Such widely different factors as infection, intoxication, trauma, muscular and nervous fatigue, extreme heat or cold, and irradiation elicit from the body a similar response and have been grouped together as types of stress. Stress implies either an inner conflict or a conflict against circumstances for which no immediate action is appropriate. It implies further that the conflict is protracted, the outcome uncertain, and that the victim is