Allergic conjunctivitis is an allergic disease caused by exposure to allergens. Because the conjunctiva is in direct contact with the outside air, it is easily exposed to airborne allergens, either actively or passively, resulting in itching, redness, swelling and tearing of the eyes. The best way to treat allergic conjunctivitis is to get rid of the allergen that causes the reaction so that the symptoms can be effectively relieved. Common allergens include the following: animal hair, fungi, dust mites and pollen. Diagnosis is based on medical history, symptoms, signs and relevant tests. The main tests are allergen skin test, conjunctival scraping and serum IgE test. The first step is to actively avoid contact with allergens by deliberately blocking contact with allergens, such as wearing a mask for pollen allergy, or changing clothes and blankets for dust mite allergy, and keeping indoor air clear. However, often allergens are not easily detected, or even if they are known, it is impossible to completely avoid contact with them because they are widely present in the living environment. Therefore, clinical treatment is performed despite the fact that many patients have not yet discovered the definitive allergen causing the disease. Topical treatment of the eye is based on the use of anti-allergic eye drops, of which there are different types: antihistamines with fast onset of action, levocabastine eye drops, emetine eye drops, etc., mast cell stabilizers with long-lasting anti-allergic effect, pyrimethamine potassium, etc., and biphasic allergy-inhibiting drugs, patanos, etc. If the symptoms are heavy and accompanied by allergic rhinitis, they also need to be used in combination with nasal drops, as well as oral anti-allergy medications. In summary, although allergic conjunctivitis is simple to treat, an individualized treatment plan based on the patient’s specific situation is needed to achieve the best results.