Now they have discovered that most ulcers are caused by a bacterial(细菌的)organism(有机体) called Hillico Bactor Pilorie or H Pilorie. H Pilorie bacteria are what make stomach produce extra stomach fluid. Doctors found that they can kill the bacteria with medicinescalled antibiotics(抗生素)。 Health experts say the discovery of a cure for ulcers can save thousandof millions of dollars in medical costs. They also believe curing ulcers will reduce the number of people who develop stomach cancer.