A medicinal aerosol formulation including 0.01-5% medicament, at least 50% by weight 1,1,1,2-tetrafluoroethane (134a), less than 5% surface active agent, and at least one compound having higher polarity than 1,1,1,2-tetrafluoroethane, and which is free of chlorofluorocarbons and propellants CHClF.sub.2, CH.sub.2 F.sub.2 and CF.sub.3 CH.sub.3.