Do tums (calcium carbonate) work?

Depends on goal: Tums (calcium carbonate) neutralize stomach acidity and can relieve symptoms of this including gerd. Tums (calcium carbonate) are a good source of calcium and can be used for this purpose. So in fact they do 'work' for these purposes.

Tums (calcium carbonate): Tums (Calcium Carbonate) can help reduce symptoms from indigestion, stomach upset & heart burn. It can be used for calcium deficiency.