CBD Oil and Breast Cancer: What You Need to Know

Medically Reviewed by Brunilda Nazario, MD on September 15, 2021

If you have breast cancer, you might be wondering if CBD oil can help ease your symptoms or treatment side effects. Maybe you've seen advertisements for CBD that make promising health claims. Or maybe you have friends who've tried it for other reasons, like anxiety or trouble sleeping.

Before you take CBD oil for breast cancer or any condition, though, it's important to look past the hype and get the facts. Here's what the research says, what the risks of CBD are, and whether it might be legal where you live.

What Is CBD?

CBD stands for cannabidiol. It's a chemical compound in cannabis plants like marijuana and hemp. CBD doesn't get you high, which makes it different from the other popular compound in cannabis, mind-altering THC (tetrahydrocannabinol).

Product makers create CBD oil by extracting cannabidiol from marijuana or hemp and then mixing it with a "carrier oil." Some forms of CBD oil come in drops or sprays you take by mouth called tinctures. Others come in oil-based capsules.

CBD products also come in forms like:

  • Creams, lotions, and balms
  • Edibles like gummies, baked goods, and infused drinks
  • Smokable hemp flower
  • Vaporizer pens

The FDA has approved only one CBD product: a prescription drug called Epidiolex. It treats seizures linked to two rare types of epilepsy and to a genetic disease that causes benign tumors.

Otherwise, there are few large, well-designed studies about CBD's effects on other medical conditions. Some research suggests that it might show promise for easing psychotic symptoms in Parkinson's disease and for anxiety tied to public speaking.

But several experts say they haven't yet seen research that proves CBD's effectiveness for problems like:

  • Pain
  • Nausea
  • Depression
  • Anxiety disorders

Does CBD Oil Show Promise for Breast Cancer?

Cannabis and oils extracted from it can't control or cure any type of cancer. But some people are curious to know if CBD oil can ease breast cancer symptoms or treatment side effects, like:

  • Pain
  • Anxiety
  • Inflammation
  • Insomnia
  • Nausea
  • Scars or wrinkles
  • Acne

While some doctors think it's possible that certain types of CBD might have benefits for cancer-related anxiety, sleep problems, and pain, research on people is lacking. For now, there are far more studies on mice and in lab dishes.

Here's what we know: Research on people has mainly looked at cancer in general rather than at breast cancer specifically. Also, the studies have focused on the effects of marijuana, not CBD oil.

Some small studies show that smoking marijuana can ease nausea and vomiting from chemotherapy. Research also shows that smoking or vaping marijuana can relieve another treatment side effect: pain due to damaged nerves. But marijuana has both THC and CBD in it -- and THC has a much stronger track record of easing pain and nausea than CBD does.

Other research from clinical trials on people shows that folks with cancer tend to need less pain medicine when they take marijuana extracts.

Lab and animal studies on cannabis compounds also show promise, although the results aren't guaranteed to translate to health benefits for people. Some of these studies show that CBD inhibits (meaning limits or blocks) certain proteins involved in breast cancer. Lab research also shows that a compound in hemp called cannabidiolic acid (which can turn into CBD when heated) has anti-inflammatory properties in human breast cancer cells.

Other studies done in lab dishes suggest that compounds in cannabis, including CBD and THC, can slow the growth of certain cancer cells or kill them. Animal research also suggests that certain cannabis compounds slow the growth and limit the spread of some types of cancer.

What Are the Health Risks?

CBD can bring on side effects like:

  • Dry mouth
  • Diarrhea
  • Less appetite
  • Drowsiness or sleepiness
  • Liver damage

It can also mix badly with medications you're on, like blood thinners.

CBD's quality varies, too, depending on where you buy it. Some commercial products:

  • Make false or unproven or health claims.
  • Have less CBD than advertised.
  • Could be contaminated with things like pesticides, heavy metals, and THC.

The bottom line: Don't try CBD oil for breast cancer without talking to your doctor first. If you're having pain or discomfort from breast cancer symptoms or treatment side effects, let the doctor know right away. They can recommend safe and effective medications, lifestyle changes, and types of emotional support to help you feel better.

If your doctor says it might be safe for you to try CBD oil, first ask them questions like:

  • Can you recommend a dispensary that sells reputable, high-quality products?
  • What type of CBD oil should I take? How much of it should I use? And how often?
  • Is there a chance it could mix badly with any medications or supplements I take?
  • Could it cause complications with my breast cancer or any other health conditions I have? (For instance, the FDA recommends against using CBD if you're pregnant or breastfeeding.)

Is CBD Oil Legal?

It mainly depends on where you live. Medical marijuana is legal for adults in 37 states as of August 2021. If you live in one of them, it's legal to buy CBD oil that comes from marijuana.

Hemp, which has much less THC than marijuana, is legal in the U.S. under federal law -- as long as it has 0.3% THC or less. Before you try to buy CBD oil that comes from hemp, though, you might want to check for any local or state restrictions.

WebMD Medical Reference



Antioxidants: "Antioxidative and Anti-Inflammatory Properties of Cannabidiol."

Clinical, Cosmetic and Investigational Dermatology: "Therapeutic Potential of Cannabidiol (CBD) for Skin Health and Disorders."

USDA PubAg: "The effect of cannabidiol on canine neoplastic cell proliferation and mitogen‐activated protein kinase activation during autophagy and apoptosis."

FDA: "What You Should Know About Using Cannabis, Including CBD, When Pregnant or Breastfeeding," "FDA Regulation of Cannabis and Cannabis-Derived Products, Including Cannabidiol (CBD)," "What You Need to Know (And What We're Working to Find Out) About Products Containing Cannabis or Cannabis-derived Compounds, Including CBD."

Medscape: "Cannabis for Pain? An Expert's Guidance," "CBD's Role in Acute Pain Relief Tied to Patient Expectations."

U.S. Pharmacist: "Pharmacist's Guide to CBD Oil."

Harvard: "Cannabidiol (CBD)-what we know and what we don't."

National Institutes of Health: "Tuberous Sclerosis Fact Sheet."

Anxiety & Depression Association of America: "Can CBD Help with My Anxiety and Depression?"

MD Anderson Cancer Center: "CBD oil and cancer: 9 things to know."

American Cancer Society: "Marijuana and Cancer." "Medical Cannabis."

Memorial Sloan Kettering Cancer Center: "Now that Weed Is Becoming Legalized, Should More People with Cancer Use Cannabis?"

Mayo Clinic: "What are the benefits of CBD — and is it safe to use?"

Reuters: "U.S. Senate Democrats roll out draft bill to legalize weed."

University of Georgia: "An Introduction to Hemp Chemistry and Lab Results."

© 2021 WebMD, LLC. All rights reserved.