In recent years, the occurrence of chronic cough patients with accompanying allergic factor has increased. The main causes of these patients’ symptoms are laryngeal allergy, atopic cough, cough variant asthma and classic bronchial asthma. We observed a case of chronic cough of unknown cause that was initially suspected to be the result of laryngeal allergy. A forty-seven-year-old female complaining of a persistent dry cough for seven months visited our clinic. She had Japanese cedar hay fever with a higher level of serum specific IgE to cedar pollen. No abnormal findings were found in CT and X-ray imaging of her chest. Peroral ingestion of H1 blocker, bronchodilator, proton pump inhibitor, antibiotics, minor tranquilizer and cough remedy were entirely ineffective and the patient was diagnosed as having a cough of unknown cause. Peroral ingestion of Bakumondoto (Mai Men Dong Tang), a Chinese blended medicine and 1% codeine phosphate hydrate powder showed tremendous effectiveness. The combined treatment of the two medicines was found to be an effective therapy for such case of chronic cough of unknown cause.
