Vitamin C has the effect of whitening and lightening spots, but it is difficult to remove spots by single use. Vitamin C is a common whitening product, which mainly uses its reducing and antioxidant effects to combine with pigmented spots in human skin, then decompose and finally discharged from the body through metabolism, so as to achieve a certain effect of light spots. However, there are strong differences in the specific effect, depending on the type and severity of the spots, the effect is also different. Vitamin C can reduce the occurrence of freckles, melasma and other melanin deposits through its own anti-free radicals and reducing the synthesis of tyrosinase enzymes, thus playing the role of light spot and whitening. Oral vitamin C is mainly absorbed by the body through the gastrointestinal tract and requires a longer period of cell turnover to improve skin tone or spots, and its effect is limited. Vitamin C should not be taken in large quantities for a long time. Excessive intake of vitamin C not only cannot be absorbed and utilized by the body, but may also lead to an increase in the amount of oxalic acid in the organism, thus increasing the risk of kidney stones. In clinical practice, doctors will let patients take vitamin C orally in appropriate amount according to the patients’ condition, and at the same time add fruit acid peeling, laser and other ways to cooperate with the treatment, generally you cannot achieve the effect of removing spots by taking or applying vitamin C topically. The doctor should test the patient’s liver and kidney function during the process of use to prevent adverse reactions. Therefore, it is recommended that patients who want to get rid of spots should have their treatments formulated by doctors and follow medical prescriptions for medication.