Helicobacter pylori is a Gram-negative bacterium with a helical bacillus shape that it's able to penetrate and colonize the stomach mucosal lining by infecting it.

The eradication treatment of H. pylori is supported by numerous consensus groups worldwide and it is generally safe and well tolerated. Standard treatment is based on multiple drug regimens. However, its effectiveness has been increasingly compromised due to the emergence of resistant strains, as well as poor adherence to treatment. Therefore, it's proposed a randomized, double-blind, placebo-controlled study whose aims are:

1. Determine whether the combination of two probiotic strains of L reuteri (Gastrus) will improve gastrointestinal symptoms when associated with four-way therapy (of any type).
2. Prove whether supplementation with Gastrus (food supplement) versus Placebo is able to reduce the gastrointestinal adverse effects of quadruple eradication therapy.

They will be determined by the GSRS gastrointestinal symptom scale in routine clinical practice.

Inclusion Criteria:

• Patients attended at the clinic visit who present a positive diagnosis of H pylori infection using different diagnostic techniques (C13 breath test, histology, urease and / or H pylori antigen in stools).
• Age between 18 and 65 years

Exclusion Criteria:

• Patients taking other probiotics 4 weeks prior to study start.
• Patients who have previously received eradicating therapy.
• Patients who are treated with NSAIDs, aspirin or other anti-inflammatory drugs either on an occasional basis (one week prior to the study) or on a chronic basis (3 weeks prior to inclusion).
• Patients who have used oral antibiotics two weeks prior to inclusion.
• Pregnancy