Yarrow
It is surprising to know that Yarrow flowers contain flavonoids, tannins, polyphenols, lactones, and resins that help a lot to reduce the amount of acid in the stomach. These flavonoids act on the main digestive nerve that is known as the vagus nerve.
However, reduction in stomach acid levels can reduce heartburn and indigestion. A person who is suffering from such kind of problems must try eating young Yarrow leaves raw in a salad or cooked in a meal. You can also make a tea of Yarrow by boiling some leaves in the water.