[en] We discuss here the case of a 49 years old man who is admitted in the emergency department in acute heart failure. He suffers of severe alcoholism and malnutrition. This heart failure is a high-output heart failure. The diagnosis is beriberi, a disease caused by a deficiency of thiamine (vitamin B1). The treatment is intravenous administration of thiamine. Clinical response is spectacular with normalization of the clinical setting within a few hours.