Ketoconazole shampoo should not be used for a long period of time; ketoconazole is a broad-spectrum antifungal medication. Ketoconazole shampoo is primarily a topical topical medication used to treat and control dandruff and its associated flaking, as well as scaling and itching. It is used twice a week for 2-4 weeks when treating dandruff and should be used as needed to control dandruff, not for long periods of time. If symptoms do not improve or worsen after 2-4 weeks of use, the medication should be discontinued and a doctor consulted. It should not be used on broken skin, the use of ketoconazole shampoo is well tolerated by most patients, a few people will experience local irritation or allergy, which may be manifested as a burning sensation of the skin, itching or contact dermatitis, and a few patients will experience dryness at the site of the medication, rashes, folliculitis, as well as alopecia, pustules, changes in the color of the hair, burning sensation of the skin, and so on. Serious allergic reactions, such as angioedema, may also occur after the use of the drug. Therefore, it is necessary to pay attention to the observation when using the drug, and consult the doctor promptly if there are abnormal manifestations.