PROBLEM TO BE SOLVED: To provide a new and safe angiotensin II 1 type (AT1) receptor antagonist, a hypotensive agent, and a medicinal composition for treating and/or preventing hypertension.SOLUTION: There are provided an angiotensin II 1 type receptor antagonist containing gnetin C or a salt thereof, a hypotensive agent, and a medicinal composition for treating and/or preventing hypertension, containing an angiotensin II 1 type receptor antagonist or a hypotensive agent.