Green’s Dictionary of Slang

bicarb n.

[abbr.]

bicarbonate of soda.

[US]S. Lewis Babbitt (1974) 299: Bad indigestion? Shall I get you some bicarb?
[US]H. Gold Man Who Was Not With It (1965) 20: She claimed stomach ache and Pauline answered she was too young for bicarb in the heart.