The object of the present invention is to provide a pharmaceutical composition optimized for the administration of a drug, particularly a drug which is only sparingly soluble in water, by way of inhalation. The present invention is a fat emulsion for inhalational administration, or a lyophilized composition thereof, which is an o/w fat emulsion comprising fat emulsion particles essentially composed of an oil component, an emulsifying agent and a drug as dispersed in water, characterized in that the average particle diameter of said fat emulsion particles lies within the range of 5˜100 nm. With the aid of a suitable inhaler, the inhalant of the invention readily yields a mist of aerosol particles fine enough to reach the alveolus; the inhalant is well amenable to size control of the aerosol particles.