Cannabidiol (CBD) is a potential therapeutic compound found in the cannabis plant. People can mix CBD with a carrier oil to create CBD oil. Evidence suggests that CBD oil may help to treat cancer symptoms, but more research is necessary.

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 cancer 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 treating cancer.

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

This article contains information on what researchers know about 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% THC federally legal. However, CBD products containing more than 0.3% 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 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 several health conditions, is non-impairing and will not cause a person to feel high.

Learn more about the differences between CBD and THC here.

Manufacturers extract CBD from the C. Sativa plant to create a CBD oil, then mix it with a carrier oil. A common extraction process that manufacturers use is the supercritical carbon dioxide method. This clean, cost-effective method 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 cannabis or cannabinoids as a cancer treatment is necessary, some evidence shows promise.

For instance, a previous 2019 literature review indicates that several studies found that CBD extracts may help to reduce cancer cell viability and prevent cancer cells from multiplying.

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 anticancer properties of CBD oil.

Due to ethical issues, investigating CBD and its use as a cancer treatment may also be difficult. 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.

CBD effects on different types of cancer

Researchers have studied the effect of CBD on specific types of cancer.


A 2019 study indicates that CBD may encourage cell death and make glioblastoma cells more sensitive to radiation.

In 2020, researchers noted that cannabinoids may reduce tumor growth in glioma cases on its own or alongside other cancer medication in test tube experiments. They also wrote that it could kill cancer cells, stop them from migrating to other body parts, and increase survival.

Breast cancer

The authors of this 2020 study also write that CBD can stop cancer cells from multiplying in breast cancer. It may also inhibit the migration and metastasis of cancer cells in aggressive breast cancer cases. Researchers found these results in both human and test tube studies.

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.

Pancreatic cancer

A 2019 review on pancreatic cancer suggests that cannabinoids may help slow tumor growth, reduce tumor invasion, and induce tumor cell death.

Colorectal cancer

Endocannabinoids can inhibit or promote the growth of colorectal cancer cells. Researchers note that the stage of a person’s colorectal cancer may be a useful factor to consider when investigating the effects of CBD on this type of cancer.

Studies have found that the anticancer effects of CBD may be dose-dependent, and scientists believe that inducing cell death is the main way that CBD can help in colorectal cancer cases.

Lung cancer

CBD may act on certain cell lines in lung cancer. The 2020 literature review writes that some research found CBD reduced the invasion of A549 cells in test tube studies by 29–63%. However, there are no published results from clinical trials that involve treating those with lung cancer with CBD.

While cancer treatments such as chemotherapy and radiation therapy can effectively treat cancer, they have various 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 Food and Drug Administration (FDA) has approved some cannabinoid-containing medications to reduce the side effects of cancer treatments. Examples include dronabinol and nabilone, 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 medication containing both CBD and THC. The FDA has not yet approved Sativex in the U.S. However, 2017 and 2018 studies found Sativex did not make statistically significant improvements in study participants’ pain.

The American Cancer Society also lists 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 there is sufficient evidence to suggest that cannabinoids can help significantly reduce chronic pain.

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.


Cancer treatment can affect a person’s sleep. This can be because of medication, stress, hospital stays, and other factors. The National Cancer Institute states that around half of all people experience sleep problems during cancer treatment.

A 2019 analysis writes that CBD may help to reduce anxiety and improve sleep. However, a 2020 systematic review wrote there is not enough evidence to back up the routine use of CBD for sleep disorders.

Click here to learn more about CBD and sleep.


Cancer treatment can also affect a person’s appetite.

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 of 2,409 people who used CBD, 6.35% experienced increased hunger as a side effect.

Recent research has produced mixed results regarding the role cannabinoids play in cancer development.

Researchers have identified a cannabinoid receptor called CB2 in immune system cells such as B-lymphocytes and natural killer cells. This suggests that there may be a 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) states that people tolerate CBD well. A 2020 study also notes that acute CBD use has few side effects, 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 notes that cannabinoid drugs may worsen symptoms of depression, mania, or other mental health conditions. However, this is more likely to result from THC and not CBD.

Learn more about CBD and depression.

Research also indicates that CBD may interact with certain medications. Therefore, people should speak with a doctor before using CBD oil or other products.

The FDA does 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, people should 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 provides certificates of analysis (COAs) 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 product, people should follow all packaging instructions 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 several forms. These can include:

  • oils to place under the tongue or tinctures to add to 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 product’s potency and the application method.

According to a 2017 review, taking up to 600 milligrams of CBD does not cause significant adverse effects. 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 anticancer 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 with a doctor before using CBD products or any other compound during cancer treatment to ensure they will not react with any current medication.

Visit our dedicated hub for more research-backed information and in-depth resources on CBD.

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