Cannabidiol (CBD) is a compound found in the cannabis plant that may have many potential therapeutic uses. By mixing CBD with a carrier oil, people can create a CBD oil. Although more research is necessary, evidence suggests that CBD oil may have some use in the treatment of cancer.

While it is too early to make strong claims about using CBD oil for cancer treatment, evidence indicates that it may help to manage symptoms resulting from the disease or its treatment.

Although initial results from small and animal studies on cancerous cells and CBD oil are promising, they are not yet conclusive. More research is still necessary to determine how effective CBD oil may be in the treatment of cancer.

A person should always check with their doctor before using CBD oil to ensure it will not interact negatively with any current medication or forms of treatment.

This article contains information on what researchers know related to CBD oil and cancer, and how to choose and use CBD oil products.

Is CBD legal?The 2018 Farm Bill removed hemp from the legal definition of marijuana in the Controlled Substances Act. This made some hemp-derived CBD products with less than 0.3 percent THC federally legal. However, CBD products containing more than 0.3 percent THC still fall under the legal definition of marijuana, making them federally illegal but legal under some state laws. Be sure to check state laws, especially when traveling. Also, keep in mind that the FDA has not approved nonprescription CBD products, and some products may be inaccurately labeled.

CBD is one of many phytochemicals present in the Cannabis sativa (C. sativa) plant. It is one of the two most well-known cannabinoids, along with delta-9-tetrahydrocannabinol (THC).

THC is the chemical responsible for the “high” that many people may associate with cannabis. CBD, which shows promise for treating a number of health conditions, is non-impairing and will not cause a person to feel high.

Learn more about the differences between CBD and THC here.

To create a CBD oil, manufacturers extract CBD from the C. sativa plant, then mix it with a carrier oil. A common extraction process that manufacturers use is the supercritical carbon dioxide method. This is a clean and cost-effective method that uses heat, pressure, and carbon dioxide to separate CBD from the plant.

Producers then dilute the CBD with a nontoxic oil to produce CBD oil. According to the National Cancer Institute, CBD oil typically contains between 1–5% CBD.

While more research investigating the use of cannabis or cannabinoids as a cancer treatment is necessary, some evidence shows promise. In 2016, researchers noted that cannabinoids may reduce tumor growth in different types of cancers in test tube and animal models.

The National Cancer Institute adds that CBD may help to enhance the uptake or increase the potency of certain drugs that doctors may use to treat cancer.

A 2019 literature review indicates that several studies found that CBD extracts may help to reduce cancer cell viability and prevent cancer cells from multiplying.

A 2019 review focusing on pancreatic cancer suggests that cannabinoids may help slow tumor growth, reduce tumor invasion, and induce tumor cell death. A 2014 study also notes that CBD may have the potential to inhibit the spread of colorectal cancer cells.

A 2019 study indicates that CBD may encourage cell death and make glioblastoma cells more sensitive to radiation. This is consistent with a 2014 review, which also suggests that cannabinoids may possess anti-tumor properties.

However, it is worth noting that research is still in its early stages. Most evidence is largely from laboratory- or animal-based studies. Therefore, more research and human studies are necessary to determine the potential anti-cancer properties of CBD oil.

Investigating CBD and its use as a cancer treatment may also be difficult due to ethical issues. Many studies investigating CBD may incorporate chemotherapy medication. Therefore, this may make it difficult to interpret how effective CBD is in treating cancer by itself.

While cancer treatments such as chemotherapy and radiation therapy can be effective in treating cancer, they can result in an array of side effects. (Most research has investigated the benefits of CBD, although CBD oil may work similarly.)

Some of the cancer side effects CBD may help to reduce include the following:


The U.S. Food and Drug Administration has approved some cannabinoid-containing medications to reduce side effects of cancer treatments. Examples include dronabinol and nabilone, which are synthetic THC medications that can help reduce nausea.

A small 2016 study on humans suggests that Sativex may also help relieve nausea due to chemotherapy. Sativex is a medicine containing both CBD and THC. The FDA has not yet approved Sativex in the U.S.

The American Cancer Society also list cannabinoids as a treatment option for chemotherapy-induced nausea and vomiting.

However, these medications are not the same as CBD oil products a person can purchase over the counter (OTC). While CBD oil may help with nausea, it will likely be less effective than prescription cannabinoid-containing medications.

Click here to learn more about CBD and nausea.


A 2020 review notes that CBD could have benefits for relieving chronic pain, improving sleep, and reducing inflammation.

A 2017 report notes that there is sufficient evidence to suggest that cannabinoids can help to significantly reduce chronic pain. A 2012 study also suggests that CBD can help to reduce pain and inflammation.

A 2017 review also found that CBD may help with chronic neuropathy pain in humans, which can be a side effect of chemotherapy and cancer.

Click here to learn more about CBD oil and pain.


A 2012 study suggests that CBD may help to increase sleep duration. A 2019 analysis also adds that CBD may help to reduce anxiety and improve sleep.

Click here to learn more about CBD and sleep.


Studies suggest that a common side effect of using products containing CBD is an increase or decrease in a person’s appetite. A 2018 review notes that in 2,409 people who used CBD, 6.35% experienced increased hunger as a side effect.

Current research has produced mixed results in regard to the role cannabinoids play in cancer development.

Researchers have identified a cannabinoid receptor called CB2, which is present in immune system cells such as B-lymphocytes and natural killer cells. This suggests that there may be link between CBD and immunity.

However, more long-term studies in humans are necessary to determine what role, if any, CBD has to play in the prevention of cancer. Additionally, as CBD oils contain roughly 1–5% CBD, they would likely have less effect than the stronger doses in prescription medications.

The World Health Organization (WHO) state that people generally tolerate CBD well. A 2020 study also notes that there are few adverse effects with acute CBD use, but chronic use may have mild effects. A 2018 article notes that more research is necessary to understand potential long-term side effects.

Research suggests that potential side effects may include:

The American Cancer Society note that cannabinoid drugs may worsen symptoms of depression, mania, or other mental illness. However, this is more likely to be the result of THC and not CBD.

Research also indicates that CBD may interact with certain medications. Therefore, it is advisable for people to speak with a doctor before using CBD oil or other CBD products.

The FDA do not currently regulate OTC CBD products. As a result, it can be difficult to know exactly what CBD products may contain. A 2017 study cautions that CBD products available online may include inaccurate labels.

When considering CBD products, it is advisable for people to choose products that:

  • are not from a company subject to an FDA warning letter
  • contain no more than 0.3% THC, per the Agriculture Improvement Act
  • have proof of third-party testing by an ISO/IEC 17025-accredited laboratory
  • pass tests for pesticides, heavy metals, mold, and microbes
  • pass product potency evaluations and safety testing
  • are from a company that provide certificates of analysis for their products

Additionally, people may also consider:

  • flavor
  • price
  • CBD potency
  • retailer’s and manufacturer’s reputation
  • customer reviews

Read our complete buyer’s guide to CBD here.

As with any CBD products, people should closely follow all instructions on the packaging and not exceed the correct dose on the label. People new to CBD oils should start with the lowest possible dosage. Once they know how their body reacts to the substance, they can gradually increase the dose.

Manufacturers sell CBD oil in a number of forms. These can include:

  • oils to place under the tongue or tinctures to add in food
  • oils in creams, lotions, or balms for topical applications
  • oils in gummies or other edibles for people to consume

Currently, there are no definitive studies on CBD’s effectiveness, so it is hard to know exactly what dosage people should use. Dosage can also vary due to the potency of the product and the method of application.

According to a 2017 review, taking up to 600 milligrams of CBD does not cause significant adverse effects. It is possible some people may be able to safely take higher amounts, but more research is necessary. A person may wish to discuss potential dosages with their doctor.

CBD may have some benefits for reducing cancer symptoms and may have some anti-cancer properties. However, research is still in its early stages. Furthermore, as manufacturers dilute CBD with a carrier oil to produce CBD oils, they may have less of a beneficial effect than other CBD products, including prescription products.

People should always talk to a doctor before using CBD products or any other compound during cancer treatment to ensure they will not react with any current medication.

For more information and resources on CBD and CBD products, please visit our dedicated hub.