The Best Questions to Ask Your Doctor About CBD

September 25, 2026 at 7:27 am

If you are thinking about trying CBD, the most important question to ask your doctor or pharmacist is whether it could interact with anything you already take. After that, ask about liver monitoring, pregnancy or breastfeeding, drug testing at work, and how CBD might combine with alcohol or sleep medications. Those are the areas where the FDA and the prescribing label for Epidiolex, the only FDA-approved CBD drug, point to real, documented risks.

Many people feel awkward bringing up CBD at an appointment. You do not need to. Clinicians can only help with what they know about, and the NIH's National Center for Complementary and Integrative Health (NCCIH) encourages telling your providers about any complementary product you use. The list below gives you ten questions to bring, plus why each one matters.

A tip before you go: bring the actual product, or a photo of the label and its lab report (certificate of analysis, or COA). A clinician can say much more about a specific product than about "CBD" in general.

Key takeaways

Ask about drug interactions first. CBD is processed by the liver enzymes CYP3A4 and CYP2C19 and can change levels of some other medicines.
Ask whether liver tests make sense. An FDA-run trial in healthy adults found liver enzyme elevations in some people taking CBD daily for four weeks.
If you are pregnant, trying to conceive, or breastfeeding, the FDA strongly advises against CBD in any form.
Pure CBD is unlikely to trigger a standard workplace drug test, but products containing THC can.
CBD can add to the sedating effect of alcohol and sleep or anxiety medications.

1. "Could CBD interact with any of my medications or supplements?"

This is the big one. According to the FDA-approved label for Epidiolex (prescription CBD), cannabidiol is broken down mainly by the liver enzymes CYP3A4 and CYP2C19, and it can raise or change levels of drugs that use related pathways, including some processed by CYP1A2, CYP2C19, and CYP2C8. The label specifically notes that CBD raises levels of an active form of the seizure medicine clobazam by about threefold.

Bring a complete list of prescriptions, over-the-counter medicines, and supplements. Our CBD and prescription medication guide explains the basics in more detail.

2. "Do any of my medicines carry a grapefruit warning?"

This is a useful shortcut question for your pharmacist. The FDA explains that many drugs are broken down by CYP3A4, and grapefruit juice can block that enzyme so more drug stays in your blood. A grapefruit warning on a label tells you a medicine depends on CYP3A4, which is also one of the main enzymes that processes CBD. It does not prove CBD will interact with that drug, but it is a good reason to ask.

3. "Should I get liver tests, before or after starting?"

In 2025, FDA researchers published a randomized trial in JAMA Internal Medicine with 201 healthy adults. People took CBD at 5 mg per kilogram of body weight per day (about 340 mg a day for a 150-pound adult) or a placebo for 28 days. Eight people in the CBD group (5.6 percent) had liver enzyme levels rise above three times the upper limit of normal, compared with none on placebo. The researchers described that dose as within the range some consumers take. The study shows why your doctor might want a baseline blood test, especially if you drink alcohol, take other medicines that affect the liver, or have liver concerns. The Epidiolex label also calls for liver monitoring.

4. "Is CBD safe for me if I am pregnant, trying to conceive, or breastfeeding?"

The FDA strongly advises against using CBD, THC, or marijuana in any form during pregnancy or while breastfeeding. It notes that high doses of CBD in pregnant test animals caused problems with the reproductive system of developing male fetuses, and that CBD products may be contaminated with substances such as THC. Ask your clinician before using any CBD if this applies to you.

5. "Could this affect a drug test?"

Standard drug tests look for a THC breakdown product, not CBD. In a study by researchers at Johns Hopkins, 100 mg of pure CBD did not produce a positive urine result under federal workplace testing cutoffs, but a CBD-dominant product that also contained THC did produce positive results. Labels are not always accurate: a 2017 JAMA study found THC in 18 of 84 CBD products bought online. If you are drug tested, ask your doctor, and your employer's policy, before you start. See Does CBD show up on a drug test?

6. "Is it safe with alcohol, sleep aids, or anxiety medication?"

The FDA warns that using CBD with alcohol or other drugs that slow brain activity, including those used for anxiety, panic, stress, or sleep disorders, increases the risk of sedation and drowsiness, which can lead to injuries. The Epidiolex label advises patients not to drive or operate machinery until they know how CBD affects them. Ask whether your specific combination is a concern.

7. "What side effects should I watch for?"

The FDA lists possible effects including changes in alertness (most commonly sleepiness, though it can also be insomnia), diarrhea, decreased appetite, and mood changes such as irritability. Ask which ones would mean you should stop, and which are worth calling about. Our CBD side effects article covers them, and CBD safety summarizes what we tell customers.

8. "How much should I start with, and how will we know if it is worth continuing?"

Hemp CBD products are not FDA approved, so there is no official dose for everyday use. Ask your clinician to help you pick a starting amount, a time frame, and one or two simple things to track, such as how you feel on waking or how you rate your day. A clear check-in point keeps you from taking something indefinitely without knowing whether it helps. Our CBD dosage guide can give you background for that conversation.

9. "Is there something else going on that I should get checked?"

People often reach for CBD because of poor sleep, stress, or aches. Those deserve their own attention. For example, NCCIH notes that loud snoring, gasping during sleep, and daytime sleepiness can be signs of sleep apnea, which needs a medical evaluation. Ask whether your symptom warrants a workup before you try any supplement.

10. "What should I look for on the label and lab report?"

NCCIH notes that over-the-counter CBD products may contain more or less CBD than labeled and may contain contaminants. The 2017 JAMA study found only about 31 percent of 84 products were accurately labeled for CBD. Ask your clinician whether a THC-free product makes more sense for you, and bring the COA to the visit. Proof posts the SC Labs results for each finished product (currently dated May 2025) on our lab testing page, so you can print them for your appointment.

FAQ

Do doctors know about CBD?

Knowledge varies. Pharmacists are a good resource on drug interactions. Even if your clinician has not studied CBD closely, they know your medications and health history, which is what matters most.

Should I tell my doctor I use CBD even if it is hemp and legal?

Yes. NCCIH recommends telling your health care providers about any complementary products you use so they can care for you safely. Legal status says nothing about interactions.

Can CBD be taken with blood thinners or seizure medicines?

Those are exactly the kinds of combinations to review with your prescriber first. The Epidiolex label documents interactions with some seizure medicines, including clobazam and valproate, and your prescriber can check the rest.