An injectable composition comprises a benzimidazole compound having an antiulcer action and a strong alkali (e.g., an alkali metal hydroxide such as sodium hydroxide) in a proportion of about 1 equivalent of the latter relative to 1 mol of the former, and is substantially free from a nonaqueous solvent. The injectable composition may comprise N-methylglucamine, and a saccharide (such as mannitol). The injectable composition may be a freeze-dried preparation. The freeze-dried preparation is dissolvable in or dilutive with a distilled water for injection or an infusion solution without a nonaqueous solvent. The injectable composition is useful as an antiulcer agent.