1. The effects of clinical inhalation anaesthetics, such as halothane and methoxyflurane, and "model" anaesthetics, such as hydrocarbons and n-alkanols, on neuronal sodium and potassium channels are reviewed. 2. Lipid-based mechanisms for the actions of anaesthetics on the gating parameters of squid axon sodium and delayed rectifier potassium currents are considered in conjunction with evidence of more specific effects in other preparations, notably a fast inactivating potassium current in Helix neurones and a voltage-gated sodium current in rat dorsal root ganglion neurones. 3. The proconvulsant actions of some inhalation anaesthetics are discussed in relation to the induction of spontaneous firing of action potentials in the squid giant axon.