The pathogenesis of palmoplantar hyperhidrosis (HH) remains unknown. A causative therapy is therefore not possible yet. Step by step treatment for palmoplantar HH is advised. This includes: topical aluminium salts, tap water iontophoresis (TWI), botulinum toxin (BTX) injections and endoscopic thoracoscopic sympathectomy (ETS). The mechanism of action of TWI has been previously studied but is still not completely understood. A widely accepted hypothesis is that the anodal current causes accumulation of H(+) within the sweat duct. It is presumed that this causes an unknown lesion in the acrosyringium that inhibits sweating. TWI is non-invasive, safe, well tolerated, efficient and cheap. The patient can perform the therapy at home without medical assistance. TWI remains the best treatment for palmoplantar HH that has defied aluminium salts. This article provides a review of the literature concerning TWI, including its historical development, its mechanism of action and its indication and also describes the method of administration of this helpful treatment.