Can I Give My Dog Tums?

Yes, with care
Calcium carbonate is commonly referenced for dogs at published doses. Published guidance for dogs: small dog: 250-500 mg; medium: 500-750 mg; large: 750-1250 mg, every 8-12h, short-term. Occasional heartburn only. Fruit-flavored versions fine; check label for xylitol in sugar-free lines.
Source: Veterinary Partner (VIN)
Get the exact range for your dog's weight

Skip it or ask a vet first if

xylitol-sweetened versionskidney diseasewith tetracyclines

The safe habit

Confirm any medication decision with your veterinarian, who knows your dog's health history and other medications. VetDose shows published reference data, not prescriptions.

See also

Other antacid / GI questions for dogs