A &ohgr;-cycloalkyl-prostaglandin E2 derivatives of the formula (I) wherein R is carboxy or hydroxymethyl; R1 is oxo, methylene or halogen atom; R2 is H, OH or C1-4 alkoxy; R3 is H, C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C1-8 alkyl, C2-8 alkenyl or C2-8 alkynyl substituted by 1-3 of substituent selected from halogen atom, C1-4 alkoxy, C3-7 cycloalkyl, phenyl, or phenyl substituted by 1-3 of substituent selected from halogen atom, C1-4 alkyl, C1-4 alkoxy, nitro, trifluoromethyl; n is 0-4; and non-toxic salt thereof, prodrug thereof and cyclodextrin clathrate thereof can strongly bind on EP2 subtype receptor. Therefore, they are useful for prevention and/or treatment of immune disease (autoimmune disease, organ transplantation, etc.), asthma, abnormal bone formation, neuron cell death, liver damage, abortion, premature birth or retina neuropathy of glaucoma etc.