PURPOSE: To provide an external drug for skin, containing a pharmacologically active substance and an oleaginous base containing a gas selected from carbon dioxide, hydrogen sulfide and radon.

CONSTITUTION: The objective external drug for skin contains (A) an oleaginous base (e.g. vegetable oil such as olive oil, almond oil, etc., animal oil such as lanolin, beeswax, beef tallow, etc., synthetic oil such as liquid paraffin, fatty acic such as hexanoic acid, or natural or synthetic fatty acid triglyceride, etc.) containing at least one kind of gas selected from carbon dioxide, hydrogen sulfide and radon, and (B) a pharmacologically active substance (e.g. analgesic anti-inflammatory agent such as ethyl aminobenzoate, antipruritic such as ichthammol, disinfection sterilizer such as phenol, astringent such as zinc oxide, emolelient such as refined sulfur, antimycotic agent such as chrysarobin, etc.).

EFFECT: Sufficient effect can be attained even at a low concentration of the pharmacologically active sustance, and the side effect of the drug can be mitigated.