It has been known for some time that Helicobactor pylori (H. pylori) infection can cause gastric cancer, and that treatment with antibiotics can prevent the development of this tumour. However, the long-term effects of eradicating H. pylori and its effects on incidence and mortality from gastric cancer are not known. Now, a study among 2,258 individuals seropositive for H. pylori who received a single treatment of amoxicillin and omeprazole has revealed that this treatment was associated with a statistically significant decrease in the incidence of gastric cancer as well as mortality compared with placebo. The benefits of one-time treatment in older patients (>55 years) were also noted even in individuals who had post-treatment infection, indicating this treatment can benefit the entire population.