This is a kind of bacteria that causes ulcers and inflammation in your stomach, and it’s one of the main causes of gastric cancer. There are different strains, some of which have a higher risk of cancer. Your doctor can test to see if you have this bacteria. H. Pylori can be treated with antibiotics, which may be another reason this kind of cancer is less common now than in the 1930s. The only way to know you have this bacteria is with a test. If you have a parent, sibling, or child who’s been diagnosed with gastric cancer, you should get tested.