The effect of the general anaesthetic, benzyl alcohol, on the nicotinic cholinergic receptor (AChR) was evaluated at the single channel level using the patch-clamp technique. Benzyl alcohol decreases both the conductance (about 2-fold with 40 mM benzyl alcohol) and the mean open time (about 2.5-fold) of the AChR channels. When modified channels are activated by high ACh concentrations, groups of brief channel openings are observed. Each group is in turn composed of a higher number of openings than in non-treated receptors. Similar modifications are observed when benzyl alcohol is applied from the cytoplasmic side of the membrane, suggesting that the general anaesthetic interacts with a nonspecific site, possibly the lipid-protein interface.