In abroad, Methacholine Chloride (Provocholine®) is used to meet the indications of the diagnosis of bronchial airway hyperreactivity in subjects who do not have clinically apparent asthma. We examined efficacy, safety and pharmacokinetics of Methacholine Chloride (name of study drug: SK-1211) in order to get approved for the airway hyperresponsiveness test in Japan.Fifteen adult healthy volunteers, fifteen adult patients with asthma and ten pediatric patients with asthma were enrolled in this study. The airway hyperresponsiveness test with SK-1211 was conducted in accordance with Japanese Society of Allergology Standard Method.When the threshold value of PC20 was 8 mg/mL, the sensitivity of adult patients with asthma was 66.7% (10/15 subjects) and the specificity of adult healthy volunteers was 86.7% (13/15 subjects). The sensitivity of pediatric patients with asthma was 70.0% (7/10 subjects). Not all subjects experienced some adverse reactions during inhalation of SK-1211, all of which were mild in severity and resolved soon with inhalation of a bronchodilator. There were no serious adverse reactions reported.The airway hyperresponsiveness test with SK-1211 was no specific concern with safety and useful in the diagnosis of bronchial airway hyperresponsiveness.