Sweating is a physiological phenomenon intended to contribute to heat regulation in order to maintain body temperature at the stable value of 37°C. We use the term hyperhidrosis [Hyper + hidrôs (sweat)] when sweating is excessive; the quantity of sweat produced considerably exceeds the volume required for thermoregulation. The neurological control responsible for sweating is provided by the hypothalamus and the sympathetic system. In some cases, hyperhidrosis, in particular in its general form, is only a symptom, the cause of which must be found. Treatment with iontophoresis involves localized palmar or plantar (or mixed) forms, which are usually idiopathic, even if an emotional context is sometimes suspected. The problems caused are significant: difficulties in performing manual tasks, cutaneous symptoms, etc ., and have social and professional repercussions. It is estimated that around 1 % of the population is affected by localized hyperhidrosis. Treatment with iontophoresis (Hyperhidrosis programme) is used to obtain lasting remission of hyperhidrosis after around ten sessions. The remission period can last up to six months, and the treatment can be started again when the signs reappear.