Bitters
Angostura bitters- it's that little brown bottle with the yellow cap the bartender usually keeps next to the Worstshire sauce and Tabasco...
No seriously it's aromatic bitters, which is a combination of water, alcohol and I think gentian -it's great for upset tummies, gas attacks...Add a few dashes to your glass of seltzer (I also add a lemon slice), super refreshing and does the job...
It's also a flavoring agent in certain cocktails -Champagne cocktail (champagne, bitters and a sugar cube, and a Manhattan (whiskey, sweet vermouth, bitters). I think you also use it in an Old Fashioned.
A friend uses it to use it for her apple pies instead of vanilla -it's got an altogether different flavor profile, sweet and a little spicy...
Hope this helps.
Monkey
"Life is a banquet - and most poor suckers are starving to death" - Auntie Mame