Aluminum Starch Octenylsuccinate is the aluminum salt of the reaction product of octenylsuccinic anhydride with starch. It is used in cosmetics at concentrations as high as 30% as an anticaking agent and a nonaqueous viscosity increasing agent. No information was available on the presence of impurities in the cosmetic-grade ingredient. When used in foods, Aluminum Starch Octenylsuccinate is identified as a modified food starch, and is subject to limitations on heavy metal residues. Oral studies using Aluminum Starch Octenylsuccinate or its related sodium salt produced no adverse systemic, reproductive, or developmental effects. Dermal injections produced no abnormal skin or systemic reactions in guinea pigs. Ocular toxicity was assessed in rabbits and using an in vitro test (chorioallantoic membrane vascular assay). In both cases no toxicity was seen. An acute inhalation toxicity study in rats was negative. Clinical tests indicated little irritation potential and no sensitization. Absent data on impurities in cosmetic-grade material, it was determined that such material should meet the same impurities requirements established for modified food starches. Based on these available data the Cosmetic Ingredient Review Expert Panel concluded that Aluminum Starch Octenylsuccinate is safe as used in cosmetic formulations provided that established limitations imposed on heavy metal concentrations are not exceeded.