[Problem] The objective of the present invention is to provide a preparation technique with which yellowing that occurs over time or in high-temperature conditions can be suppressed and excellent storage stability can be provided even when diclofenac and/or a salt thereof and a tocopherol and/or derivative thereof are included in a pharmaceutical composition for external use that includes water. [Solution] Provided is a pharmaceutical composition for external use that includes diclofenac and/or a salt thereof, a tocopherol and/or derivative thereof, and water, wherein by mixing in lactic acid and/or a salt thereof, yellowing that occurs over time or in high-temperature conditions can be suppressed, and excellent storage stability can be provided.本發明之目的係提供即便在包含水之外用醫藥組成物中，包含雙氯芬酸(diclofenac)及/或其鹽以及生育酚及/或其衍生物，仍可抑制在經時或高溫條件下所產生之黃變，並具備優異的保存安定性之製劑技術。本發明之解決手段係藉由在包含雙氯芬酸及/或其鹽、生育酚及/或其衍生物、以及水之外用醫藥組成物中，調配乳酸及/或其鹽，便可抑制在經時或高溫條件下所產生之黃變，並可具備優異的保存安定性。
