Two-week-old baby blood in the stool can be seen in diarrhea disease, constipation, intestinal polyps and other conditions. 1. diarrhea disease: such as infectious diarrhea disease, clinical symptoms of diarrhea, due to pathogen invasion and increased frequency of stool can appear local intestinal mucosal damage, the phenomenon of blood in the stool, such babies are often accompanied by fever or vomiting and other symptoms, improve the stool routine examination can assist in the diagnosis. 2. Constipation: if the dry stool affects defecation, local intestinal mucosal damage can occur, the phenomenon of bloody stools, often accompanied by a significantly longer interval between defecation, such babies intervene to relieve constipation, bloody stools can disappear. 3. Intestinal polyps: these babies are mostly manifested as painless chronic bloody stools, usually not accompanied by painful defecation, rectal fingerprinting and colonoscopy can assist in the diagnosis. 4. other: such as milk protein allergy, can appear digestive symptoms, such as diarrhea, bloody stools and other phenomena, such babies often have a history of eczema. Two-week-old baby blood in the stool, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.