The vasoactive intestinal polypeptide (VIP) is a powerful dilatator in a number of vascular beds. Plasma VIP is increased in active physical exercise and in transcutaneous nerve stimulation. Plasma VIP has in this study been measured during other physiotherapeutic procedures causing skin vasodilatation, such as connective tissue massage and heat packs. Plasma VIP levels and skin temperature of fingers and toes were measured in 12 patients before and at various intervals following a 30 min connective tissue massage. No significant increase in the plasma VIP was found. The same was true in a pilot study using heat pack treatment. It is suggested that somehow VIP is more involved in the vascular response to active physical activity and peripheral nerve stimulation than to passive procedures like connective tissue massage and heat pack treatment.