There are the following contraindications to taking vitamin B: 1. If there have been obvious gastrointestinal diseases, or the stomach has been a large cut type of surgery, or there has been a ruptured esophagogastric varices bleeding, there has been upper gastrointestinal bleeding or there are obvious gastric ulcers, duodenal ulcers, in the active period is a strict contraindication to taking vitamin B. 2. Because vitamin B is an acidic vitamin, taking it at this time will induce serious bleeding in the upper gastrointestinal tract. 2, eating vitamin B contraindications and kidney, liver and kidney insufficiency, in some patients with acute liver and kidney insufficiency or liver and kidney failure can not take vitamin B. Because the vitamin B group is detoxified by the liver and metabolized by the kidneys, if you take vitamin B at this time will increase the load on the liver and kidneys, thus causing multiple organ insufficiency.