Twenty-eight patients with spastic and obstructive vascular disease were treated with intravenous regional guanethidine (IRG). The drug was injected into the affected hand or foot in doses of 10 or 20 mg, respectively. Temperature and strain-gauge plethysmography curves of the extremity were recorded before treatment, and three to four times during the subsequent 10 days. The effects of IRG, as observed by clinical laboratory examinations, were good in 8 of 12 patients. But in patients suffering from Bürger's disease or from major vessel obstructive disease, the results were not as good. However, in most patients IRG proved beneficial in relieving pain, an effect which sometimes outlasted objective improvements. IRG treatment is a simple and safe method for prolonged chemical sympathectomy.