The patient who complains of hyperhidrosis presents the physician with a diagnostic and therapeutic challenge. Patients who present with generalized hyperhidrosis are, in general, adults whose sweating occurs both during the waking and sleeping hours. Such patients require a search for a cause that may sometimes be as simple as a drug that they are taking for some medical disorder. Occasionally a systemic illness may account for the onset of hyperhidrosis and a thorough exam and appropriate testing may be necessary to identify the cause. Most patients with primary or essential hyperhidrosis present in childhood or adolescence and have a problem localized to their hands and/or feet. They have a physiologic disorder not a psychiatric or endocrinologic disease. A number of systemic, topical, surgical, and electrical remedies are available for the treatment of hyperhidrosis. Patients with hyperhidrosis of the palm or soles deserve a trial of conservative therapy, iontophoresis in particular, before aggressive surgical techniques that carry with them the risk of lifelong troublesome side effects are offered.