When someone has a peptic ulcer, it means there is a sore in their tummy or the first part of their small intestine. This sore can happen because of some bad bacteria or if they take certain medicines that can hurt their tummy. When someone has a peptic ulcer, they might feel a lot of pain in their tummy, feel sick, or even throw up. Doctors can give them medicine to help them feel better and heal the sore in their tummy.