Data indicate that, independent of illness, the social environment of the hospital may produce stress for child surgical patients and their mothers. For the children, stress may result in elevated temperature, pulse rate, and blood pressure; post-operative emesis; disturbed sleep; and an extended period of recovery. Experimental data indicate that social interaction with hospital personnel, providing information and emotional support, may reduce a mother's stress and change her definition of the hospital situation. This in turn may reduce a child's stress and have indirect but profound effects on his social, psychological, and even physiological responses to hospitalization and surgery.