ROTA ROD is the instrument meant for studying the effect of diazepam on the muscle grip strength of mice. A versatile built with LST chips is equipped with Four Two/Three compartments and Four/Two/Three independent 4 digits. Digital milliseconds timer for measuring the fall-off time of the mice. It is also equipped with a motor coupled with rotating rod whose speed can be varied with the help of the front panel knob marked with an arrow or speed less than 10 RPM. One of the important pharmacological actions of ant anxiety of agents of benzodiazepine class of drugs is muscle relaxing property. The skeletal muscle relaxation together with taming or calming effect these agents reduce anxiety and tension. The loss of muscle-grip is an indication of muscle relaxation, this can be easily checked in animals, using ROTAROD. The difference in the fall of time from the rotating rod between the control and diazepam treated animals is taken an index of muscle relaxation. The rate of rotation of the rod should be adjusted such that normal mouse can stay on the rod for an appropriate period of time.