Whether or not taking a ketotifen pill every night for a dry cough is effective is determined by the cause of the dry cough. If the cough is determined to be caused by allergies, taking one ketotifen tablet per night may be effective. Ketotifen is an antihistamine with anti-allergic properties and is mainly used to treat allergic rhinitis and allergic bronchial asthma. The anti-allergic effect is stronger and the effect lasts longer, but this drug is generally recommended to be taken once in the morning and once in the evening. However, this drug has adverse reactions such as drowsiness, tiredness and weakness, and when using it, you should avoid driving motor vehicles and working at heights, and avoid drinking alcohol. This drug is contraindicated for those who are allergic to ketotifen. However, there are many causes of dry cough, different causes of different treatments, such as upper respiratory tract infections, acute and chronic bronchitis, lung infections, lung tumors, bronchial foreign bodies, gastroesophageal reflux disease, etc., the use of ketotifen is ineffective. Therefore, patients with dry cough should go to the hospital as soon as possible, improve the examination to clarify the cause of the disease, standardize the treatment under the guidance of the doctor, and avoid self-medication.