PURPOSE: To obtain a medicine for diabetes of type II independent of insulin containing specific sesquiterpene analogs and a salt thereof as active ingredient.

CONSTITUTION: The objective medicine for diabetes contains compounds expressed by formulas I and II and a basic compound salt thereof as active ingredient. The compound expressed by formula I is dissolved in a basic solvent to form an equilibrium mixture with the compound expressed by formula II as a tautomer and resultant mixture is directly able to be used as active ingredient. As the basic compound forming salt, hydroxide or carbonate of alkali (earth) metal or organic amount (e.g. ethylamine or piperazine), etc., are exemplified. Formulation carrier such as filler, binder, wetting agent, disintegrator, surfactant or lubricant is used together with the active ingredient to form a formulation of tablet, pellet, powder, solution, capsule, granule, suppository or injecting agent, etc. Administration dose is 0.1-50mg (as amount of active ingredient) to an adult per 1 day.