Helicobacter pylori is a Gram-negative spiral-shaped bacterium, member of epsilon-Proteobacteria specifically colonizing the gastric epithelium of humans. It causes one of the most common infections worldwide, affecting about half of the world's population. However, it should be noted that the prevalence of H. pylori, particularly in the Western world, has significantly decreased coinciding with an increase of some autoimmune and allergic diseases, such as asthma. Various epidemiological studies have also documented a negative association between H. pylori colonization and the presence of GERD (gastroesophageal reflux disease) and risk of esophageal cancer. Additionally, an upward trend of obesity recently observed in inhabitants of developed countries raised a question about the relationship between H. pylori infection and the human body mass index. The first part of this review describes common, recommended anti-H. pylori treatments. The second part, presents the results of recent experiments aimed at evaluating the association between H. pylori infections and gastro-esophageal diseases, the level of stomach hormones, the human body mass index and allergic diseases. Although some studies suggest an inverse association of H. pylori infection with some health problems of the modern world such as asthma, obesity or GERD, H. pylori should be considered as a harmful human pathogen responsible for serious and sometimes lethal diseases. Thus, many scientists advocate the eradication of H. pylori.