Infant spitting up with blood may be caused by gastrointestinal bleeding, oral ulceration, nipple ulceration. 1. Gastrointestinal bleeding: babies spitting up with blood may be caused by upper gastrointestinal bleeding due to vitamin K deficiency, stress, gastritis, gallbladder lesions, and the child will also have black stools, blood in the stools, pale, poor mental health and other symptoms. 2. Oral ulcers: babies spitting up with blood may also be caused by bleeding due to rupture of the oral mucosa. 3. Nipple breakage: when the mother’s nipple breaks down and bleeds, the child will suck the blood in when sucking on the milk, and when spitting up the milk will be spat out and bleed, such mothers should pay attention to the use of the healthy side of the breast to feed, to avoid secondary nipple infection. There may be other reasons for babies to spit up with blood, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.