Does omeprazole cause cancer?

Medically reviewed by Gerardo Sison, Pharm.D.

Licensed Pharmacist

Updated Feb 4, 2026 • Published Jan 12, 2026

Fact Checked

Omeprazole has not been proven to directly cause cancer, but research on its association with stomach cancer is mixed. Some studies suggest a possible increased risk, while others do not, and experts note that omeprazole may mask stomach cancer symptoms, delaying diagnosis rather than causing the disease itself.

Want a deeper look? Read our full analysis: Omeprazole side effects and how to avoid them

Medical disclaimer: This content is for general informational purposes only and does not constitute medical advice. Always consult your healthcare provider before making changes to your medication regimen.

Medically reviewed by Gerardo Sison, Pharm.D.

Licensed Pharmacist

Gerardo Sison, Pharm.D., graduated from the University of Florida. He has worked in both community and hospital settings, providing drug information and medication therapy management services. As a medical writer, he hopes to educate and empower patients to better manage their health and navigate their treatment plans.

Written by Karen Berger, Pharm.D.

Licensed Pharmacist

After receiving her doctorate from the University of Pittsburgh School of Pharmacy, Karen Berger, Pharm.D., has worked in both chain and independent community pharmacies. She currently works at an independent pharmacy in New Jersey. Dr. Berger enjoys helping patients understand medical conditions and medications—both in person as a pharmacist, and online as a medical writer and reviewer.

Does omeprazole cause cancer?

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