Essential hyperhidrosis of the upper limb is readily corrected by cervico‐dorsal sympathectomy. The clinical picture of this condition, the mechanisms of sweat production and the results of treatment are discussed.SummaryTreatment of essential hyperhidrosis of the upper limb in five patients by bilateral cervical sympathectomy is reported.There was no mortality and little morbidity in this series, and all patients were relieved of their distressing symptom