Poison is shown to be a Caucasian female with long pink, somewhat rugged, hair. She wears a black cap, a choker, blue cutoff shorts, red high heels, and a tanktop cut just below her breasts. In Final Fight Revenge and some artworks, her hair is shown to be purple instead. She wears several armbands around her right arm and has chains and a pair of handcuffs suspended off her shorts.
Source: Wikia, "http://www.streetfighter.wikia.com/wiki/Poison", available under the CC-BY-SA License.