Twitching is frequently used in horse management because of its sedating and pain-relieving effects. In this study, the effects on the horse?s nervous system by twitching were investigated by thermography of the skin temperature. The temperature is regulated by the sympathetic nervous system through postganglionic sfincters at the capillaries of the skin. The effects on the endocrine activity have also been studied by the measuring of ACTH and cortisol in blood plasma.