MAJOR — Use With Caution
🔴 MAJOR — CBD significantly increases warfarin levels. Do NOT combine without close medical supervision and frequent INR monitoring.
Evidence level: STRONG
CBD can dramatically increase warfarin levels in your blood, making your blood dangerously thin and raising serious bleeding risk.
CBD inhibits CYP2C9 and CYP3A4, significantly increasing warfarin levels and INR, leading to dangerous bleeding risk.
If you must use CBD with warfarin, your doctor needs to monitor INR very frequently (weekly minimum) and likely reduce warfarin dose. Never start CBD without telling your anticoagulation clinic.
Use caution. Many botanicals affect blood clotting — ginkgo, garlic, ginger, turmeric, and dong quai all have antiplatelet activity that can amplify Warfarin. St. John's Wort can REDUCE anticoagulant effectiveness. Take at separate times and inform your prescriber about all herbal supplements. Request more frequent INR monitoring if on warfarin.
Elderly, those with liver disease, high CBD doses
Unusual bruising, nosebleeds, blood in urine/stool, prolonged bleeding from cuts, sudden severe headache
Inform your anticoagulation clinic BEFORE starting CBD. Request frequent INR monitoring.
Blood thinners have narrow safety margins. Instead of CBD Oil, consider safer options: CoQ10 (with INR monitoring), vitamin D3, or probiotics — these have minimal anticoagulant interactions. Always inform your anticoagulation clinic about any supplements.
CBD can dramatically increase warfarin levels in your blood, making your blood dangerously thin and raising serious bleeding risk.
Use caution. Many botanicals affect blood clotting — ginkgo, garlic, ginger, turmeric, and dong quai all have antiplatelet activity that can amplify Warfarin. St. John's Wort can REDUCE anticoagulant effectiveness. Take at separate times and inform your prescriber about all herbal supplements. Request more frequent INR monitoring if on warfarin.
Unusual bruising, nosebleeds, blood in urine/stool, prolonged bleeding from cuts, sudden severe headache
Blood thinners have narrow safety margins. Instead of CBD Oil, consider safer options: CoQ10 (with INR monitoring), vitamin D3, or probiotics — these have minimal anticoagulant interactions. Always inform your anticoagulation clinic about any supplements.
Inform your anticoagulation clinic BEFORE starting CBD. Request frequent INR monitoring.
Or browse the full interaction database (121,000+ pairs).