Objective To study the effect of gallamine triethiodide (GT) on the increased afferent discharge from the muscle spindle caused by succinylcholine (SCh). Methods The nervous filaments of rats were separated from tibial nerve innervating the gastrocnemius muscle, and afferent discharge from the muscle spindle was recorded. SCh of a certain dose was injected after 4 minutes of injection of a certain dose of GT. The effect of suppression by GT on the increased afferent discharge from the muscle spindle caused by SCh was measured by counting the decrease in discharge peak frequency (DPF) and maximum increase frequency (MIF) and by counting the time of peak frequency (PF) appearing delayed than the controls. Results When the dose of SCh was 0.005mmol/kg, the dose of GT was 0.005mmol/kg, 0.010mmol/kg and 0.020mmol/kg, DPF reduced to 67.2%, 52.5% and 37.1% of the controls, respectively; MIF reduced to 61.4%, 40.2.% and 25.4%; PF appearing time delayed 43.9s, 64.3s and 80.4s than the controls. When the dose of GT was 0.005mmol/kg but the dose of SCh was 0.010mmol/kg, DPF and MIF reduced to 83.3% and 77.8% of the controls, respectively; PF appearing time delayed 22.5s than the controls. Conclusion GT has a remarkably suppressive effect on the increase in afferent discharge from the muscle spindle induced by SCh. The suppression of GT is dose-dependent, and the action of SCh and GT on muscle spindle is in competition.