Remedies or preventives for diseases with a need for immunoregulation, diseases with a need for inhibition of inflammation, diseases with a need for regulation of tumor necrosis factor production, diseases with a need for regulation of fungal growth, diseases with a need for regulation of cell adhesion or disease with a deed for induction of heat-shock protein, which contain as the active ingredient at least one compound selected from among cyclopentenone derivatives represented by general formula [I], optically active isomers and salts thereof, wherein R 1 and R 2 are the same or different and each represents hydrogen, an aliphatic group, an aromatic group or an aromatic aliphatic group.