Acute asthma is a common medical emergency. The goals of therapy are therefore to remove hypoxaemia, improve airflow limitation and prevent death. We describe the case of a 51-year-old woman with asthma admitted to Emergency Department after complaining acute respiratory failure and coma. The improvement of respiratory failure, after administration of high concentration of oxygen, beta-2 agonist and corticosteroids, wasn't associated at improvement of consciousness. The deterioration of blood gases dont justified coma. Having a suspicion the patient takes some benzodiazepines, we administered flumazenil and the patient improved adequately.