The symptoms of feeling weak after a bowel movement are mainly caused by infectious diseases of the digestive tract. Common types of diseases include adenoviral enteritis, bacterial dysentery, and acute gastroenteritis. Inflammatory lesions in the digestive system cause congestive swelling and functional disorders in the surface mucosa of the stomach, intestines and other digestive tract organs. As a result, a large amount of water and nutrients in the body cannot be properly decomposed and absorbed, they are excreted from the body in the form of excrement, resulting in symptoms such as diarrhea and loose stools. However, the possibility of other diseases such as small intestine malabsorption syndrome, large intestine polyps and intestinal stroke cannot be ruled out. Because of the above types of diseases, the normal functioning of the human digestive system tissues can also be seriously affected, thus causing such adverse reactions to occur.