For several years the protease chymotrypsin has been among the available adjunctive treatments for traumatic injuries in which tissue hemorrhage and edema present a problem.1The toxicity of this material has been studied, and it has been found to be relatively nontoxic.2However, being protein in nature it might be expected to elicit a sensitivity reaction in susceptible persons. A survey of the literature revealed a report on only one such sensitivity reaction.3T