Hyperhidrosis, or excessive sweating, is a common disorder which produces a lot of unhappiness. An estimated 2%-3% of Americans suffer from excessive sweating of the underarms (axillary hyperhidrosis) or of the palms and soles of the feet (palmoplantar hyperhidrosis). Although neurologic, endocrine, infectious, and other systemic diseases can sometimes cause hyperhidrosis, most cases occur in people who are otherwise healthy. Heat and emotions may trigger hyperhidrosis in some, but many who suffer from hyperhidrosis sweat nearly all their waking hours, regardless of their mood or the weather.