B vitamins have certain side effects: 1, causing digestion and absorption dysfunction, gastrointestinal dysfunction, because most of the B vitamins belong to water-soluble vitamins, so it will make the gastrointestinal tract release too much gastric acid, will corrode the gastrointestinal tract mucosa, especially will cause gastric ulcers and other problems affecting digestion and absorption, when there will be acid reflux, heartburn, nausea and other clinical symptoms. 2, B vitamins taken too much will also The kidney burden, because the human kidney is the main place to metabolize drugs or detoxification and filtration of one of the main organs, such as vitamin B overdose will make the kidneys work overdrive, so a long time to take will lead to renal insufficiency. 3, vitamin B overdose will also cause a certain burden on the liver, affecting the normal excretion and metabolism of the liver.