Author's Note: This article represents a combination of knowledge from the skin care industry (Dr. Marenus) and the dermatologic community (Dr. Draelos). The first of the two-part article discusses current understanding of the etiology of cellulite while the second part presents purported treatments. Cellulite is a condition affecting 85% of postadolescent women characterized by dimpled tissue on the upper outer thighs, posterior upper thighs, and lower buttocks. A better understanding of the etiology of cellulite has been obtained through ultrasonic analysis of the upper thigh and buttock tissue demonstrating herniation of the subcutaneous fat into the dermis. The initial changes leading to cellulite formation appear to be deterioration of the dermal matrix and vasculature, particularly loss of the capillary networks, leading to excess fluid retention within the dermal and subcutaneous tissues. This loss of the capillary network is thought to be due to engorged fat cells clumping together and inhibiting venous return. A variety of treatments, to include xanthines, herbal derivatives, heating, massage, and skin kneading, have been put forth as possibly reducing the dimpled skin appearance.