Fecal red blood cell examination is a routine item of stool, which can understand the digestion and absorption function and help diagnose digestive system diseases. There are no red blood cells in normal feces. Inflammation or bleeding of the lower intestine can occur, such as dysentery, ulcerative colitis, colon cancer, rectal polyp, acute trematode, etc. The fresh red blood cells in feces are pale yellow and slightly refractive disc-shaped. Bacterial dysentery has fewer red blood cells than white blood cells, which are scattered and normal in shape. There are more red blood cells than white blood cells in patients with amebic dysentery, many of which exist in piles and are broken.