Perivascular sympathectomy has been thought to cause distal adrenergic denervation. We performed perivascular sympathectomy for a distance of 1 cm. on two common digital arteries in the right hands of two anaesthetised Macaca arctoides monkeys. Four days later, samples were taken for glyoxylic acid-induced fluorescence examination of the operated and opposite control hand. The distal adrenergic nerves were morphologically normal in appearance after the perivascular sympathectomy. The operation should perhaps be called adventitectomy rather than perivascular sympathectomy and its positive effects may be due to the loss of adventitial support for the vasospastic arteries rather than adrenergic denervation.