PURPOSE: To obtain a medical composition having excellent nitrogen monoxide synthetic enzyme-inhibiting action and useful for curing an affection derived from infarct or ischemia, etc., endotoxic and hemorrhagic shock, etc., containing a specific 2-aminopyridine derivative and a carrier. CONSTITUTION: The objective agent contains a medically effective amount of (A) a compound of the formula [R -R are each H, a (substituted) alkyl, a (substituted) alkenyl, a (substituted) alkinyl or an alkoxy wherein adjacent two combine to a group of the formula: -(CH2 )n ((n)is 3-6) and R -R are not simultaneously H] or its salt (e.g. 2-amino-4-methyl-6-propylpyridine) and a medically allowable amount of (B) a carrier.