() is linked to chronic gastritis, duodenal or gastric ulcers, and gastric cancer (GC). Because the oral cavity is the first component of the gastrointestinal tract (GIT) and the entrance point for , it has been proposed as a possible reservoir of . As a result, a putative oral-oral transmission pathway of poses the possibility of whether personal contact, such as kissing or sharing a meal, might trigger transmission. As a result, several investigations have been done on this issue using various approaches for detecting in oral and stomach samples. Furthermore, the relationship between and gastrointestinal disorders has yet to be studied. The evidence for the association between and gastric diseases and their complications is still a controversial subject due to the existing literature in this review. The goal of this comprehensive review was to collect all available published articles and critically evaluate existing investigations looking into the relationship between oral contamination and the danger of gastric complications. Few studies indicated an association between and gastric diseases. Furthermore, more longitudinal randomized clinical studies to further investigate the association between and gastric diseases are warranted.