Twenty-seven subjects with vasospastic diseases: 13 primary and 5 secondary Raynaud phenomenon (RP), 3 primary RP treated with raubasin 60 mg/day, 6 acrocyanosis and 9 normal subjects were studied in a standardized experimental set (thermostatic chamber), recording cutaneous digital micro-vascular reactions to cold and heat exposure by laser Doppler flowmetry, a relatively new method for the objective and reliable assessment of blood flow in the cutaneous microvasculature. The data suggest that patients with vasospastic disease have a defect in local microvascular flow regulation, that is revealed by low temperature exposure. The major difference between primary and secondary RF was recovery time (stop reaction) after cold test, that is easily recorded by this instrumental set. The morphology of the recording and the flow recovery time of acrocyanosis were found to be similar to those of secondary RF.