I never suffered with Heartburn bad enough to really cause problems, just a nuisance more then anything. It was suggested to me to try tea made from various Mints, which fortunately I quite enjoy especially the Lemon Balm and Peppermint....I genuinely do not know how well or even if they actually work at all but Heartburn is something that I have not suffered from now for several years. I do know that Coffee, Tea, and other drinks and foods can aggravate heartburn so it certainly didn't hurt to replace at least a couple of cups a day with the mint tea. You can buy the various dried herbs but in truth it's hard to stop them taking over if you grow them for yourself. They also have a multitude of other uses from food additives to insect (including midge/mosquito) repellants.
certainly replacing tea/coffee with herbal tea isn't a bad idea if you suffer from heartburn. Mints are good for the sort of indigestion that produced feelings of bloating and discomfort in the lower G.I. tract as they relax the smooth muscle and hence help with that spasmodic, colicky indigestion.
However if you are suffering from heartburn with acid reflux, mints are not a good idea fro the same reason - they relax the pyloric sphincter which in turn can exacerbate the acid reflux. In this case, if you want to stick with a herbal solution, meadowsweet would be a very good bet as it balances stomach acid levels.