A short clinical trial of Methoxyflurane, a new potent fluorinated ether, is reported. This agent is non-toxic, non-irritating, non-explosive and can be used with the ordinary vapourisers. Any degree of relaxation can be achieved with it. It can be used with carbon dioxide absorbers and does not seem to increase cardiac irritability. Recovery period is usually quiet. Its disadvantages are slow induction when used alone and hypotension if anaesthesia is too deep. We feel that further work is desirable to estimate its post-operative analgesic effects more fully and to assess the effect of adrenaline on the heart when used with this drug.