A two-arm, double-blind, randomized, placebo-controlled study investigating the efficacy of a probiotic preparation developed as supportive supplementation of probiotics in patients with reflux.

The objective of this trial is to evaluate the effect of the probiotic dietary supplement on the diversity and composition of the gut microbiome in patients diagnosed with GERD who are on PPI therapy. The study will also monitor changes in the oral microbiome and the impact of probiotic supplementation on patient quality of life and GERD symptoms.

Patients will take the probiotic preparation, 2 tablets twice daily (morning before meals and evening after meals). The experimental phase will last 6 weeks. Patients in the control arm will receive placebo. Supplementation will be discontinued if adverse effects occur.

Oral and rectal swabs will be taken before and after administration of the preparation. Patients will monitor their symptoms using a questionnaire.

Inclusion Criteria:

• Diagnosed GERD.
• Stable health without current complications.
• Patients on stable pharmacological PPI therapy (rabeprazole).

Exclusion Criteria:

• Use of probiotics or prebiotics within the last 4 weeks.
• Pregnancy or breastfeeding.
• Systemic antimicrobial therapy within the last 4 weeks.
• Infectious disease of the respiratory or gastrointestinal tract within the last 2 weeks.
• Serious chronic disease that could affect study results, including cancer, diabetes, inflammatory bowel disease, diagnosed SIBO.
• Prior surgeries, especially fundoplication and resections of the esophagus or stomach.
• Patients with psychiatric or cognitive disorders.
• Hypersensitivity to components of the investigational product.