How long it takes for loratadine to work for allergies varies depending on the individual’s body type and degree of allergy. Loratadine is a commonly used anti-allergy drug and is a highly effective and long-lasting antihistamine for the treatment of allergic diseases. It usually takes half an hour to take the drug and reaches its maximum effect in 8-12 hours. It is mainly used for the treatment of acute and chronic urticaria, allergic rhinitis, allergic conjunctivitis, etc. It can effectively relieve various symptoms caused by allergy, such as sneezing, runny nose, itchy nose, nasal congestion, itchy skin, etc. The dosage for mild to moderate allergy can be referred to the instruction manual, while severe allergy is recommended to take combined treatment of hormones and antihistamines in hospital. The dosage must be determined according to the degree of the patient’s condition, and the time to effect is usually consistent, but interference factors such as vomiting and drug reaction must be excluded. During the treatment of loratadine, attention should be paid to avoid re-exposure to allergens, and the treatment course should be based on symptom control, with symptoms, and the use can be stopped when the symptoms disappear.