Can I Give My Cat Tums?

Yes, with care
Calcium carbonate is commonly referenced for cats at published doses. Published guidance for cats: 125-250 mg per cat, every 12-24h. Rarely indicated; vomiting cats need a vet, not antacids.
Source: Veterinary Partner (VIN)
Get the exact range for your cat's weight

Skip it or ask a vet first if

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The safe habit

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