Peppermint is a salicylate....for some who are salicylate sensitive, it should be avoided.
It does calm the digestive tract and is helpful for many with IBS and digestive spasming...but there are many precautions as well.
Tons of peppermint tea isn't a good thing.
It causes heartburn for good reason...it relaxes the upper sphincter...owie! I can't drink much of it either, but do find that peppermint gum relaxes me and clears my thinking. Maybe it's just the very act of chewing gum.
This is an excellent link regarding its uses, contraindications and precautions.