B vitamins are water-soluble, B contains yellow riboflavin, when the intake of too much, the body can not be completely absorbed and used, the remaining part are metabolized by the kidneys to the urine, too much riboflavin stained the urine yellow, so the urine when urinating yellow, this is a normal phenomenon of B vitamin metabolism, will not harm health. After stopping the use of B vitamins, the color of urine can return to normal, or drink more water during the treatment can also make the yellow color of urine light, so there is no need to worry about the yellow urine during taking B vitamins.