Levamisole is an imidazothiazole chemical most frequently used as an antihelminthic agent in cattle. Over the last decade, levamisole has been increasingly encountered as an additive in both powder and crack cocaine. A white powder with a “fish scale” appearance, the chemical is physically similar to powder cocaine. In vivo, levamisole is metabolized to aminorex, a compound with amphetamine-like psychostimulatory properties and a long half-life; a priori, this property allows levamisole to potentiate and prolong the stimulatory effects of cocaine while bulking up the drug to increase profit for the dealer. As use of cocaine cut with levamisole becomes more prevalent, complications directly attributable to the chemical are increasingly being recognized.