A goal of primary importance to cosmetic manufacturers is to produce a finished product that will gain consumer acceptance. While promotion, packaging, and fragrance may initially entice the consumer, what is in the package will ultimately determine if there will be subsequent repeat purchases. Formulation acceptability, for the consumer, is a combination of performance in use, shelf stability, and product esthetics. Product rheol-ogy plays a significant role in defining and controlling these attributes. Esthetics, beyond fragrance, may include clarity and color, skin feel upon rub-in, ease of flow or removal from packaging and upon application, and product consistency in the package.