Helicobacter pylori (H. pylori) is still infecting more than half of the population in many countries, although the prevalence is decreasing. As a main cause of chronic gastritis, peptic ulcer, and malignant gastric tumors, H. pylori places a heavy burden on developing countries and regions with high infection rate. In the last decade, the eradication rates of conventional regimens based on proton pump inhibitors (PPIs) plus antibiotics have been decreasing. Antibiotic resistance and decrease of drug compliance caused by adverse effects were the two main reasons for eradication failure. Moreover, H. pylori treatment causes dysbiosis of gut microbiota and increases the expression of antibiotic resistance gene. Therefore, eradication of H. pylori is facing a great challenge, and effective and safe methods are needed. To reduce adverse effects, improve drug compliance and increase eradication rates, certain probiotics were added to conventional regimens in several clinical studies. Probiotics were more or less shown to reduce adverse effects in the vast majority of clinical studies, but whether probiotics can improve the eradication rate of H. pylori remains controversial. Meanwhile, several studies focusing on the impact of probiotics on gut microbiota during H. pylori eradication have been published recently. Thus, we conducted a randomized, double-blind, placebo-controlled trial aiming to evaluate the effects of probiotics combining with 14-day bismuth quadruple therapy on H. pylori eradication.