Objective　To investigate the effects of ethanol on the transmission at the neuromuscular junctions(NMJ) and the possible mechanism thereby.Methods　The effects of ethanol on the endplate potential(EPP) and miniature endplate potential(MEPP) of sciatic nerve-sartorius muscle preparations of 20 adult toads(Bufo bufo gargarizans) were studied in vitro by means of intracellular microelectrode recording.Results　Ethanol could cause the changes in EPP amplitude so as to influence the transmission at NMJ,and the effects apparently depended on the concentration of the ethanol. A proper concentration of ethanol could produce a significant increase in EPP amplitude and therefore facilitate the transmission at the NMJ.A proper concentration of ethanol also could produce a significant increase in MEPP frequency but had no influence on MEPP amplitude.Conclusion　Ethanol can increase the quantal number of transmitters released from presynaptic part.That may be one of the reasons why ethanol can facilitate the transmission at the NMJ.