The present invention relates to a therapeutic agent or prophylactic agent for a disease requiring enhancement of nerve growth factor (NGF) production upon treatment or prevention, an enhancing agent for nerve growth factor production, and a food, beverage or feed for enhancing nerve growth factor production, characterized in that each comprises as an effective ingredient a compound selected from the group consisting of soyasaponin compounds, soyasapogenin compounds, glycyrrhizin and salts thereof. In addition, the present invention relates to a novel soyasaponin compound and a novel soyasapogenin compound, having an action for enhancement of NGF production.