I recently started taking 400 mg of b2 daily for migraines and i have more frequent bowl movements that tend to be loose and yellow.. is this normal?

See below: Riboflavin is yellow in color but is not a know cause of diarrhea. Loose stools may be coincidental. You may consult this site for info: https://umm.edu/health/medical/altmed/supplement/vitamin-b2-riboflavin For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.