TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Properties: The polyhydroxyl compound has hydroxyl value of 300-1870 mg/g or 1870-3000 mg/g or less, preferably 300-1870 mg/g. Preferred Composition: The polyhydroxyl compound has 2 hydroxyl groups, 3 or more hydroxyl groups, or 4 or more hydroxyl groups. The polyhydroxyl compound has branched or cyclic aliphatic hydrocarbon group, in which the 2 or more hydroxyl groups are coupled with mutually different carbon atom. The polyhydroxyl compound having two hydroxyl groups is 3-20C polyhydroxyl compound having hydroxyl value of 300-1870 mg/g. The polyhydroxyl compound having 3 hydroxyl groups is 4-20C polyhydroxyl compound having hydroxyl value of 300-1870 mg/g. The thia-forming agent contains thiocyanate or thiourea. The mixing index ( alpha ) of epoxy compound (B) and thia-forming agent (C) is 1-10, measured by the ratio of amount (( alpha )t) (in moles) of substance of sulfur atom used for generation of episulfide group included in thia-forming agent, and amount (( alpha )e) (in moles) of substance of epoxy group contained in an epoxy compound. The mixing index ( beta ) of polyhydroxyl compound (A) and thia-forming agent (C) is 0.01-0.5, measured by the ratio of mass (( beta )t) (in g) of thia-forming agent, and mass (( beta )o) (in g) of polyhydroxyl compound. The epoxy equivalent of epoxy compound is 55-700 g/equivalent. The epoxy compound has partial structure of (III), (IV), (V) or (VI).R1-R15=H or 1-10C organic group.Preferred Process: The manufacture of episulfide compound involves substituting sulfur atom of thia-forming agent (C) by oxygen atom, and generating epoxy group of epoxy compound, and further involves regenerating thia-forming agent (C) and reacting epoxy compound (B) with regenerated thia-forming agent (C). ACTIVITY - Insecticide; Herbicide; Antiinflammatory; Antiallergic; Gastrointestinal-Gen.; Antiarteriosclerotic; Anticoagulant; Thrombolytic; Respiratory-Gen.; Dermatological; Immunosuppressive; Endocrine-Gen.; Antidiabetic; Cytostatic; Antimicrobial. No biological data given.    MECHANISM OF ACTION - None given.