The toxicity of second-generation dispersants and component surfactants to a wide range of marine organisms is concisely reviewed. Recent studies are particularly emphasized. The paper offers a current perspective on oil spill dispersant toxicology, a prerequisite to understanding the toxicology of chemically dispersed hydrocarbons. Known lethal and sublethal thresholds are summarized for various dispersants (concentrated, water-immiscible, water-miscible). Existing information on the comparative toxicology of surfactants and dispersants is evaluated; the data base on a current formulation (Corexit^® 9527) is thoroughly examined. Current studies in our laboratory with brine shrimp and endemic marine copepods are briefly described. Factors known to influence the toxicity of dispersants are described. The sites and physiology of toxic action of dispersants, though incompletely understood, are discussed; respiratory and nervous systems appear to be primary targets of action. Hypothesized relationships between dispersant toxicity and effectiveness, and the toxicity of chemically dispersed oil are discussed. Recommendations for future research are also given.