Abstract
The effect of reaction temperature on the serum cholinesterase activity of normal individuals and of persons with inherited enzyme variants has been studied. Gross anomalies have been noted in those phenotypes most sensitive to the muscle relaxant suxamethonium. It is suggested that the inactivation of cholinesterase variants at normal body temperature may be a contributing factor to the prolonged paralysis encountered in such cases. A true index of serum cholinesterase activity is obtained only when the estimation is performed at 37°C.