Documented studies support the emerging idea that drug enantiomers could have different pharmacological activity. Our bibliographical data have shown that so far no report has been published on the pharmacological activity of individual enantiomers of methocarbamol. This study was conducted to characterize the muscle relaxant activity of methocarbamol enantiomers. The rotarod test was used to compare the muscle relaxant activity of racemic methocarbamol and pure enantiomers after intraperitoneal administration of the enantiomers to mice. The results show that (+)-R-methocarbamol has higher muscle relaxant activity compared with racemic methocarbamol or (-)-S-methocarbamol.