Doctors believe that eating meat and drinking tea are the most likely to cause constipation. Some people think that eating meat and seafood and drinking tea from time to time can help digestion, but they don't know that a large amount of tannic acid in tea combined with protein will produce astringent protein tannic acid, which will slow down intestinal peristalsis, thus prolonging the time of feces staying in the intestine, easily forming constipation and increasing the possibility of toxic carcinogens being absorbed by the human body. Stomach pain is caused by eating seafood and fruit together. Fish, shrimp and algae are rich in protein and calcium. If they are eaten together with fruits containing tannic acid, it will not only reduce the nutritional value of protein, but also combine calcium in seafood with tannic acid to form new indigestible substances. This substance can irritate the stomach, causing discomfort, stomach pain, vomiting, nausea and other symptoms.