There is no data to support the specific days to see the effect of hydroquinone cream, and its efficacy is mainly related to the severity of the disease and so on. The indications for hydroquinone cream are mainly the treatment of melasma, freckles and post-inflammatory hyperpigmentation spots. It usually needs to be applied for several weeks before the pigmented spots gradually reduce, and if there is no improvement in the lesions it is still necessary to continue using the medicine for several weeks. When the color of the lesions returns to normal, the medication should be gradually reduced. If no improvement is seen after 2 months of use, the drug should be discontinued or other forms of treatment should be used as directed by the physician. After the use of the drug may appear skin burning sensation and other irritation, or skin rash and other allergic reactions, it is recommended to stop the drug in a timely manner. This drug is contraindicated for those who are allergic to it, pregnant women and children under 12 years of age. In addition, it is recommended that patients use hydroquinone cream under the supervision of a doctor, and should not use it privately.