The present invention provides an extract obtainable by extracting a plant belonging to Umbelliferae, or a processed product thereof, with a water-containing alcohol; a process for preparing the extract; a therapeutic agent or prophylactic agent for a disease accompanying an abnormality in an amount of insulin or insulin response and/or diabetic complications, characterized in that the therapeutic agent or prophylactic agent comprises as an effective ingredient the extract as defined above; an agent for an insulin-mimetic action, characterized in that the agent comprises as an effective ingredient the extract as defined above; a food, beverage or feed, comprising the extract as defined above; an agent for enhancing glucose uptake into a cell, characterized in that the agent comprises as an effective ingredient the extract as defined above; to an agent for inducing differentiation into an adipocyte, characterized in that the agent comprises as an effective ingredient the extract as defined above; and an inhibitory agent for aldose reductase, characterized in that the agent comprises as an effective ingredient the extract as define above.