There are numerous folk remedies among them are baking soda, a teaspoon in warm water, as well as apple cider vinegar, 1 teaspoon by mouth after a meal.
Among the others are calcium, and magnesium tablets. The active ingredients in tums, and Rolaids with out the alluminum.
Acid ease contains Kelp which is a natural antacid that will reduce the acid in the body, and is available from amazon. Formulated by Dr. Teitalbaum, a renown natural holistic doctor.
My article on IBS https://hubpages.com/health/IBS-Irritable-Bowel-Sy... covers the dosage amounts and gives other helpful advice. I hope it helps:)