Taking vitamin B2 with very yellow urine is caused by drug staining, which is a normal phenomenon and not a disease state. Vitamin B2 belongs to the riboflavin class of drugs, which is absorbed by the body after taking orally and excreted out of the body through urine, and the phenomenon of yellow staining of urine will occur, and the phenomenon of deepening and adding yellow color to urine will occur. Therefore, during the period of taking the drug, we should drink more water appropriately, about 1500-2000ml per day. If necessary, we can properly alkalize the urine, such as taking one sodium bicarbonate tablet orally twice a day for one week, and observe whether the phenomenon of yellow urine has improved. By drinking a lot of water, the color of urine can become lighter after dilution. However, the phenomenon of yellow urine may occur as long as the medication is taken. Oral vitamin B complex preparations can also appear yellowish urine, as well as sulfonamide antibiotics, which can also appear yellowish urine after taking.