Complex comprises alpha -cyclodextrin and a halogenated ether (at least 3 wt.% of total weight of the complex). An independent claim is also included for preparing the above complex, comprising (a) preparing an aqueous solution of alpha -cyclodextrin, (b) adding the halogenated ether to the aqueous solution, and (c) separating the precipitated complex. ACTIVITY : Anesthetic. No biological data given. MECHANISM OF ACTION : None given.