All patients will receive quadruple eradication therapy for 10 days with Omerazole 20mg x2, Amoxicilin 1g x2, Clarithromycin 500mg x2 and Metronidazole 500mg x2. The patients will be randomised into two groups. The first group will receive one capsule of probiotics x2 two hours before or after meal for 15 days and the second group placebo (capsule with same composition and colour with probiotic) x2, two hours before or after meal for 15 days as well.

The probiotic (Lactolevure, Uni-Pharma, Athens) contains four probiotic strains known for their effectivness and safety, Saccharomyces Boulandrii (1.5 BU/capsule), Bifidobacterium Lactis BB-12 (1.75 BU/capsule), Lactobacillus Acidodophilus LA-5 (1.75 BU/capsule) and Lactobacillus Plantarum (0.5 BU/capsule).

Patients with H.Pylori infection establised after a uper GI endoscopy and gastric biopsy will receive quadruple eradication therapy for 10 days with Omerazole 20mg x2, Amoxicilin 1g x2, Clarithromycin 500mg x2 and Metronidazole 500mg x2. The patients will be randomised into two groups. The first group will receive one capsule of probiotics x2 two hours before or after meal for 15 days and the second group placebo (capsule with same composition and colour with probiotic) x2, two hours before or after meal for 15 days as well.

The probiotic contains four probiotic strains known for their effectivness and safety, Saccharomyces Boulandrii (1.5 BU/capsule), Bifidobacterium Lactis BB-12 (1.75 BU/capsule), Lactobacillus Acidodophilus LA-5 (1.75 BU/capsule) and Lactobacillus Plantarum (0.5 BU/capsule).

Patients will report in a specific questionnare the presence or absence of symptoms suggestive of side effects associated with the Abx administered (i.e flatulance, abdominal pain, diarrhoea, regurgitation, vomiting).

All patints will be subjected to urea breath test one month after the completion of treatment in order to verify HP eradication.

Inclusion Criteria:

• Established Helicobacter Pylori Infection

Exclusion Criteria:

• Pregnancy
• Lactate
• Previous eradication therapy for HP.
• Course of antibiotics and/or probiotics one month prior to stydy entry
• Course of PPI's, H2- antagonst and antacids two weeks prior to study entry
• Known allergy to antibiotics that will be used in study
• Coronary disease, heart failure,malignancy,thyroid disease, pulmonary disease or other serious disease as per medical judgment