The invention relates to the benzopyran compounds of formula (I), or the salts thereof, in which, the bond between 3 and 4 positions is a single or double bond; R.sub.1 represents a hydrogen atom or a C.sub.1-6 alkyl that can be substituted; R.sub.2 represents a hydrogen atom, a C.sub.1-6 alkyl that can be substituted or an aromatic carbocyclic or aromatic heterocyclic group that can be substituted. The invention also relates to a process for preparing such compounds or their salts as well as the use of such compounds or their salts in the preparation of the medicine against type II diabetes mellitus. ##STR00001##