Ketotifen side effects and hazards are drowsiness, dry mouth, conjunctival congestion, etc. Ketotifen is divided into oral preparations, nasal preparations, eye drops, etc., different preparations have different side effects and hazards. ⒈ oral preparations (tablets, capsules, oral solutions) and nasal preparations (nasal drops, nasal inhalers, nasal sprays): common side effects and hazards are drowsiness, dry mouth, tiredness, nausea and other gastrointestinal reactions. Dizziness, headache, weight gain, and sluggishness are also sometimes seen. PEPPER FUMARONTIFEN EYE DROP: Stinging sensation is experienced by a few patients, but it does not affect the use of the product. Other patients may experience allergic symptoms such as eyelid dermatitis, blepharitis, or conjunctival congestion, corneal erosion, etc. When the above symptoms occur, the medication should be stopped immediately and medical attention should be sought. Patients who are allergic to the above drugs should be prohibited from using them to avoid adverse effects. If you need to use the drug, you need to use it under the guidance of a doctor, do not use it blindly on your own, so as to avoid improper use of medication and delay the condition.