Amoxicillin is not used to treat enteritis. Amoxicillin belongs to the penicillin class of antibiotics and is relatively good for treating gram-positive cocci and bacilli, such as for infections of the body surface and inflammation of lymph nodes, which are treated with amoxicillin with some effect. Enteritis is usually infected by gram-negative bacteria, such as E. coli and so on, so amoxicillin is ineffective or less effective in treating enteritis. If a patient has enteritis, he or she needs to be treated with oral second- or third-generation cephalosporins, as well as broad-spectrum antibiotics, such as quinolones, levofloxacin, ciprofloxacin, etc. If the abdominal pain worsens or if there is a significant increase in blood in the stool, the patient needs to be examined and treated at the hospital.