Stomach cancer is a kind of malignant tumor. This kind of disease occurs mainly due to various factors that lead to unlimited proliferation of histocytes. A healthy person cannot get cancer from a person with cancer due to infection. Infectious diseases are transmitted through close contact with a person with an infectious disease, sharing a meal, or respiratory droplet inhalation, resulting in the development of an infectious disease in a healthy person. Having any of these similar behaviors with a cancer patient does not cause cancer. Cancer cells from a cancer patient cannot usually live in another healthy person’s body. A healthy person’s immune system can recognize foreign cells and destroy them, and cancer cells from stomach cancer are no exception. Some families may have a high incidence of the disease, and this condition is not actually a transmission of stomach cancer between family members. Rather, stomach cancer has a genetic link. It may also be related to family members having similar unhealthy lifestyles, such as diet and habits like smoking and drinking. Family members may all be exposed to the same cancer-causing factors, including drinking water, air and so on. All these factors are the reasons why stomach cancer has a familial high incidence. It cannot be considered that stomach cancer is contagious. Family members, friends and colleagues sometimes stay away from people close to them after they have developed stomach cancer for fear of being infected. This is a rather wrong approach. For people with cancer, it will make them feel isolated and lonely, and they will easily lose their confidence to overcome the disease, so they should be encouraged in general.