The yellow-green color of urine after taking vitamin B2 is caused by drug staining, not by disease, so there is no need to worry. It is recommended to stop taking the drug early after the course of treatment, and the color of urine can gradually return to normal color after immediate discontinuation of the drug. Vitamin B2, also known as riboflavin, is excreted in its original form in urine after oral administration, which is manifested as yellow or yellow-green color change in urine, without any symptoms of urinary irritation, frequency, urgency, painful urination, etc. After drinking more water appropriately, the color can be restored to light yellow or clear color. In addition to vitamin B2, there are other drugs clinically that exist to cause yellowish or yellow-green color of urine after taking, such as 21 gold vitamins, vitamin B complex or furan-based antibiotics, sulfonamide antibiotics, all of which can cause yellowish color of urine, all of which are not accompanied by any urinary irritation symptoms. All that is needed is to stop the medication early, or to drink plenty of water while taking the medication.