Retinoic acid drugs for the treatment of skin diseases are considered a milestone in the history of dermatological treatment. The second generation of Avitamin is a representative of oral retinoic acid drugs, which is a metabolite of avitaminate and has comparable efficacy to avitaminate. Because of its stronger biological activity, shorter half-life (about 50 hours) and less side effects of accumulation in the body, in 1997, the US FDA officially approved Avia to replace Avia ester and approved it as the first-line drug for the systemic treatment of psoriasis. Avelox mainly regulates the metabolism of keratin-forming cells and has immunomodulatory and anti-inflammatory effects, and is effective in most psoriasis. There are differences in dose, duration and efficacy of treatment for different types of psoriasis. It is more effective for pustular psoriasis and erythrodermic psoriasis, and also for the common type, but it is usually recommended to combine the drugs to improve the efficacy. It is not recommended as a routine treatment because of its inaccurate efficacy in the arthritic type. At present, the recommended therapeutic dose of Avelox is 0.5~1.0mg/kg.d. There is no significant difference between the therapeutic efficacy of imported Avelox (new digason) and domestic Avelox (Fang Xi), but the price of imported drug is nearly ten times higher than that of domestic drug. In terms of pharmacoeconomics, domestic Fang Xi has a higher efficacy-price ratio. For the treatment of pustular psoriasis, it is recommended to start with a full dose of 25-50mg/d, which can be increased or decreased depending on the severity of the disease. The dose should be reduced gradually (e.g. 10mg every two weeks) after the disease is controlled and the lesions have subsided. The maintenance dosage is usually 10-30mg/d for 8-12 weeks, and then slowly stop the drug. In erythrodermic psoriasis, the dose used is slightly less than in pustular psoriasis, and the onset of action is slightly slower, with efficacy occurring in about 2-3 weeks, and the total duration of treatment is longer, usually requiring 3-6 months of maintenance therapy. It is recommended to administer the drug in small doses, starting at 10-30mg/d, and gradually increasing the dose until it becomes effective, with an effective dose of 30-50mg/d. The dose should not be reduced too quickly or too early, otherwise it may lead to relapse. For common psoriasis, Avia is not preferred. For severe plaque psoriasis, the combination of Avia and other drugs can be chosen to improve the efficacy. The initial dose is 20-30mg/d, and the dose can be gradually increased until satisfactory efficacy is achieved, then the dose can be reduced and maintained. The efficacy of Avia on arthritic psoriasis is uncertain, and the reported efficiency is mostly around 50% or even lower, so it is not used as the drug of choice. Most of the clinical reports on the efficacy of treatment for various types of psoriasis show that it is best for pustular and erythrodermic types, followed by the common type, and the worst for arthritic types, with the efficiency ranging from 50% to 100%. The efficacy rate ranges from 50% to 100%. Treatment with Avastin for 4-6 weeks without effect should be discontinued and replaced with other effective drugs. For pediatric use, Aviva is recommended for generalized pustular, erythrodermic, and severe plaque psoriasis. The starting dose is 0.25-0.5mg/kg.d, with the maximum amount not exceeding 1mg/kg.d. The dose should be reduced after significant improvement of the disease, and the appropriate dose should be maintained according to the disease and individual response. The potential risk of Avelox affecting growth and development in children has influenced its use in pediatric patients. However, more clinical observations have shown that under closely monitored use, with a maximum dose of no more than 1 mg/kg.d, systemic use of retinoic acid in children is generally safe, and no significant effects on growth and development have been found for either short-term or relatively long-term dosing. The most serious side effect of retinoic acid for women of childbearing age is teratogenicity, and it is recommended that women of childbearing age stop taking retinoic acid for two years before becoming pregnant to ensure safe childbirth. Elderly people are prone to drug accumulation and significant toxic side effects due to decreased liver and kidney function and slow biometabolism. The dosage should be reduced as appropriate for elderly patients to reduce accumulation and toxic side effects. For other common side effects such as dryness, flaking and itching of skin mucosa, emollients, moisturizers and anti-itching agents can be used to reduce them. Regularly monitor blood lipid, blood routine, liver and kidney function to prevent and reduce the damage to liver and kidney function and blood system of patients, and ensure the safety of drug use.