Allergic conjunctivitis is usually ordered for about 3 days, but after the disappearance of the symptoms under the guidance of the doctor to renew the drops for another 1 to 2 days to consolidate the effect of treatment. Allergic conjunctivitis is mostly caused by allergic reactions when patients are exposed to allergens. Patients can use relevant anti-allergic eye drops, such as sodium cromoglycate eye drops, under the guidance of a doctor after they are free from allergens, and the symptoms will generally be relieved after about 3 days of use. Then you can continue under the guidance of the doctor for another 1~2 days to consolidate the effect of treatment. Avoid re-exposure to allergens during the medication period to avoid affecting the efficacy of the medication. When allergic conjunctivitis occurs, it is recommended to seek medical treatment in time, you can do allergen testing to clarify what kind of substances you are allergic to, avoid contact with allergens in daily life, and use medication under the guidance of a doctor.