The drug component of Darex Ointment is carbotriol, which is a vitamin D3 analogue. It is a new type of preparation completely different from traditional topical drugs, which acts by inhibiting the proliferation of keratinocytes and inducing the differentiation of keratinocyte items in the normal direction, thus inhibiting the overproliferation of psoriatic keratinocytes, causing them to differentiate towards normal, reducing infiltration and hypertrophy, and clearing protruding papules and scales to restore them to normal. Darex ointment is characterized by the fact that it can be used repeatedly over a long period of time without reducing its efficacy, and does not cause sudden relapses or rebound of psoriasis due to discontinuation of the drug, and is odorless and does not contaminate the skin or clothing. The use of Darex is to apply a small amount of the ointment to the affected area of the skin, once in the morning and once in the evening, or alternate with other topical medications. After a week of using Darex, the lesions will slowly fade away, and the patient can gradually reduce the number of times and the amount of medication during the process, and stop using the medication a week after the lesions have completely faded. The main side effects of Darex Ointment are local irritation and transient itching, which can gradually disappear after a few days of continued use. When applying the ointment, be careful to avoid applying it to normal skin and wash your hands after applying it. The face, armpits, groin and skin folds are more sensitive and prone to skin irritation, so the drug should not be used. Care should be taken to wash off any residual drug on the hands after application. It is also important to note that the extensive application of the drug in patients with large skin lesions may cause excessive transdermal absorption of the drug, resulting in effects on calcium and phosphorus metabolism, so the total amount of drug used in adults should not exceed 100 g (3 ointments) per week. In a small number of patients, a mild increase in blood calcium may occur if more than 100 g/week is administered, but it will recover after discontinuation of the drug. In addition, Darex should not be applied to more than 40% of the skin area. Animal studies have not found any teratogenic effects of Darex Ointment, but the safety of its use in pregnant and lactating women has not been fully established and should be used with caution under medical supervision.