Last updated: October 2026
Yes, tell your surgical team you take CBD, and expect to stop it before surgery. There’s no UK guideline specific to CBD, but many hospitals ask you to stop herbal remedies and supplements about one to two weeks before an operation. CBD can interact with some anaesthetic, sedative and blood-thinning medicines. Always follow your pre-op team’s advice.
Below: why anaesthetists care about CBD, when to stop, what to tell your team, cannabis vs CBD, and when you can restart.
Why it matters before surgery
| Concern | Why |
|---|---|
| Medicine interactions | CBD blocks liver enzymes that break down many medicines, including some sedatives and painkillers used around surgery |
| Blood thinners | A case report found CBD raised warfarin levels, increasing bleeding risk |
| Drowsiness | CBD can add to the sedating effects of anaesthetic and pain medicines |
| Hidden THC | Some CBD products contain THC, which can affect heart rate, breathing and anaesthetic dosing |
See can CBD interact with medication? and the grapefruit warning explained.
When to stop CBD
Follow your hospital’s instructions. Where no specific advice is given, many hospitals ask people to stop herbal remedies and supplements about one to two weeks before planned surgery. CBD stays in the body for days, and longer with regular high doses. Don’t stop prescribed medicines unless your team tells you to. See how long CBD stays in your system.
For emergency surgery, just tell the team what you take and when you last took it.
What to tell your surgical team
- The product name and type (oil, capsules, balm, vape)
- How much CBD you take a day, and how often
- When you last took it
- Whether it’s full spectrum or contains THC (bring the label or lab report)
- Any other supplements, such as turmeric, ginkgo or fish oil, which can also affect bleeding
Be honest about any cannabis use too. It’s confidential, and it helps the anaesthetist keep you safe.
Cannabis and THC: a bigger issue
Regular cannabis use is linked with needing more of some anaesthetic drugs, and with breathing and heart rhythm effects during anaesthesia. That’s mostly about THC, not THC-free CBD, but it’s one more reason to tell your team exactly what you use.
Taking CBD after surgery
Ask your team before restarting, especially if you’ve been prescribed strong painkillers, blood thinners or antibiotics. See CBD and antibiotics. Many people wait until they’ve finished post-operative medicines. If you restart, begin at a low amount. The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
FAQs
Should I stop taking CBD before surgery?
Usually yes. Tell your team you take it and follow their advice; many hospitals ask you to stop supplements about one to two weeks before.
Does CBD affect anaesthesia?
It can interact with some sedatives and painkillers by slowing how the liver breaks them down, and can add to drowsiness.
Do I need to tell my anaesthetist I take CBD?
Yes. Tell them the product, amount and when you last took it, and about any cannabis use.
Can CBD increase bleeding?
It can raise levels of warfarin and may interact with other blood thinners. Tell your team if you take either.
When can I start CBD again after surgery?
Ask your surgical team. Many people wait until they’ve finished strong painkillers and other post-operative medicines.
Sources
- Laudanski K, Wain J. Considerations for cannabinoids in perioperative care by anesthesiologists. J Clin Med, 2022.
- Mann DK et al. Marijuana use and its impact on outpatient anesthesia. Anesth Prog, 2026.
- Grayson L et al. An interaction between warfarin and cannabidiol: a case report. Epilepsy Behav Case Rep, 2018.
- emc. Epidyolex: summary of product characteristics (interactions).
This guide is general information. Always follow your surgeon’s and anaesthetist’s instructions.
