Has anyone taken slippery elm for gastritis? I have bile on my stomach causing inflammation?

It does appear that Slippery Elm can be used for gastritis.

GI/Urogenital effects

When slippery elm preparations are taken internally, they cause reflex stimulation of nerve endings in the GI tract, leading to mucus secretion. This may be the reason they are effective for protection against stomach ulcers, colitis, diverticulitis, gut inflammation, and acidity. Slippery elm also is useful for diarrhea, constipation, hemorrhoids, irritable bowel syndrome, and to expel tapeworms. It also has been used to treat cystitis and urinary inflammations.

https://www.drugs.com/npc/slippery-elm.html