The main function of the colon is to absorb water, so its function has been destroyed and water cannot be absorbed, which finally causes diarrhea, including some water and electrolytes. After colon cancer breaks down, the mucous membrane is damaged, and some bloody stools will appear, along with some liquid and mucus, so it causes diarrhea. Therefore, if a patient with colon cancer eats poorly, he must take some rehydration every day to make up the physiological needs, about 1500-2000cc of electrolytes, sugar, protein, amino acids, trace elements, etc., so as to achieve physiological balance.