It would depend on what is causing the indigestion. If it is an ulcer, or other gastric issue, peppermint and ginger may cause more problems.
If it is from what you eat, you will need to change dietary habits.
Slippery Elm Bark powder is the best instant, natural remedy for indigestion. It coats and soothes all the way down with it's mucilaginous content. You can sip it as a tea, or buy lozenges. The lozenges are usually sold in the cold and flu isle, as it is also good for colds.