Dicloretadine has a low incidence of adverse reactions and fewer side effects than loratadine. Loratadine is mainly metabolized by the liver, with a half-life of 8~14h and a peak time of about 1.5h, and its metabolite is mainly desethoxycarboxylated loratadine. The main metabolite is desethoxycarboxylated loratadine. Desethoxycarboxylated loratadine is also known as diclofenac tartrate, so the active metabolite of loratadine in the human body is diclofenac tartrate, which can be metabolized directly without the liver, with a faster onset of effect and a more sustained action, and the half-life can reach 17~24h. The study showed that the incidence of adverse reactions in the test group of Desloratadine was significantly lower than that in the control group of Loratadine, and the therapeutic efficacy rate was significantly higher than that in the control group of Loratadine, compared with the control group of Desloratadine in the treatment of urticaria. Desloratadine and loratadine are second-generation antihistamines, both can be used for the treatment of urticaria, relief of itchy eyes, runny nose, nasal congestion, itchy skin and other symptoms of allergic diseases, the side effects are similar, mainly headache, drowsiness, fatigue, nausea, vomiting and other adverse reactions, patients with severe hepatic insufficiency, pregnant and lactating women need to be careful with the use. It is recommended that patients consult a physician or pharmacist before taking diclofenac or loratadine, under the guidance of the drug.