Finally, an aspect that needs comment is the reaction to injection of rocuronium. The authors state that injection of intramuscular rocuronium "…elicited vigorous movement (e.g., extremity movement against gravity) in 50% of patients…" and attributed this to light anesthesia. One would expect less reaction to pain only from a minor stimulus such as an intramuscular injection during 1 MAC of halothane anesthesia. Recently, however, rocuronium has been reported to cause pain after intravenous injection. [2,3] Fifty-two percent of patients to whom a subparalyzing dose of rocuronium had been administered complained of pain; of these, 12% experienced severe pain. [2] Therefore, some intrinsic irritating property of rocuronium causing pain on injection rather than the "light" anesthesia may be the cause of the reaction described.