You can generally take Tums (calcium carbonate) and Pepto-Bismol (bismuth subsalicylate) together. They work in different ways to relieve stomach symptoms, so there’s no widely recognized dangerous interaction between them for most people. That said, a few cautions are worth noting:

• Individual medications and conditions: If you’re taking other medicines (such as certain antibiotics, anticoagulants, or antifungals) or have conditions like ulcers, kidney disease, or a history of gastric bleeding, check with a clinician or pharmacist. Some drugs can interact with the active ingredients in these products or affect absorption.
• Dosing and timing: Avoid taking high doses of calcium-containing products or Pepto-Bismol for extended periods. If you’re using multiple over-the-counter products, space them out to minimize any potential absorption issues and follow package directions.
• Side effects and warning signs: Pepto-Bismol can cause darkened stools or tongue; Tums can cause constipation or, with very high doses, a rebound increase in stomach acid after stopping. If symptoms persist beyond a few days, worsen, or you develop severe abdominal pain, vomiting blood, or black/toulike stools, seek medical care.

If you’re taking other medications (especially aspirin, anticoagulants like warfarin, or specific antibiotics), or if you have any underlying health issues, it’s best to confirm with a healthcare professional before combining these. If you’d like, share your current meds and health conditions, and a more personalized assessment can be provided.