It is not recommended to take vitamin C tablets one a day for a long period of time, and if you need to take them for a long period of time for a specific reason, you should use them under the guidance of your doctor. Vitamin C is widely found in nature. A large number of fruits are rich in vitamin C, such as sour jujube, winter jujube, kiwi, sea buckthorn, orange, tangerine and so on. For example, every 100g of kiwifruit contains about 62mg of vitamin C, while the recommended daily intake of vitamin C for healthy adults is 100mg. Also some vegetables are not low in vitamin C. Therefore, if you are trying to prevent vitamin C deficiency, you only need to eat a reasonable diet with balanced nutrition, and there is no need to take extra vitamin C tablets. If there is vitamin C deficiency, such as bleeding gums, etc.; or iron deficiency anemia need oral vitamin C to promote iron absorption, should not take vitamin C tablets for a long time, but should be under the guidance of the doctor, according to the course of treatment, and regular checkups, if the symptoms improve significantly, you need to stop the drug. Long-term vitamin C consumption is prone to some side effects, such as increasing the risk of urinary stones. If you suspect that you have a vitamin C deficiency, it is recommended that you actively seek medical attention to clarify the diagnosis and then follow the doctor’s instructions for medication.