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• Early lab research shows that two cannabis compounds, THC and CBD, have potent anti-ovarian cancer properties.
• The study found that CBD and THC work synergistically, reducing cancer cell growth, spread, and survival in multiple ways.
• The findings could one day pave the way for new adjunct therapies that support both treatment effectiveness and patient quality of life.

Two compounds found in cannabis show potent anti-tumor effects when exposed to ovarian cancer cells, suggesting they could play a role in future therapeutic research.

Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the two most widely studied compounds found in cannabis. THC is the primary psychoactive compound, while CBD is a non-intoxicating compound.

Cannabis is used therapeutically for conditions ranging from nausea to chronic pain. Both THC and CBD belong to a class of compounds known as cannabinoids, which work on the body’s endocannabinoid system.

Cancer treatment is one of the most active areas of research for CBD, THC, and cannabis more broadly.

These compounds are powerful antiemetics, particularly useful for easing chemotherapy-induced nausea. They have also demonstrated promising anticancer effects in laboratory studies across several cancer types, including brain, breast, lung, and prostate.

One noticeable gap in research has been studies focused on gynecologic cancers, including ovarian cancer.

However, new laboratory research, published in Frontiers, is beginning to address that gap and may help lay the groundwork for future therapies.

Researchers found that, as in other laboratory cancer models, CBD and THC killed ovarian cancer cells and slowed markers of tumor growth.

“Our findings are generally consistent with existing literature showing that CBD and THC can act as potential adjuncts to cancer therapy,” said Siyao Tong, MD, an attending obstetrician and gynecologist at First Affiliated Hospital of Jinzhou Medical University, China, and first author of the study. 

“Both CBD and THC demonstrated clear inhibitory effects on ovarian cancer cells, and their combination, particularly at a 1:1 ratio, showed the strongest anticancer activity,” Tong told Healthline.

Other experts have hailed the research as a compelling step forward in the search for new cancer treatments.

“This is a field that is very much looking for new approaches,” said Elena Ratner, MD, a professor of obstetrics, gynecology, and reproductive sciences at Yale School of Medicine, who wasn’t involved in the research.

“This is all very early in the research, so we don’t know exactly what this will mean, but we are increasingly thinking of newer agents and newer ways of targeting cancer and understanding the biology of disease, so this absolutely has potential,” she told Healthline.

Cannabis compounds targeted cancer cells

Tong’s team conducted a variety of in vitro studies exposing ovarian cancer cells to CBD and THC in laboratory experiments. 

Notably, they experimented with two different ovarian cancer cell lines — one platinum-resistant and one platinum-sensitive. Platinum sensitivity reflects how well a cancer cell responds to platinum-based chemotherapy drugs, such as cisplatin and carboplatin, which are standard treatments for ovarian cancer.

Both lines respond to exposure to CBD and THC, though the platinum-resistant line responded better at higher doses.

Both THC and CBD also demonstrated “selective cytotoxicity,” meaning they were able to kill ovarian cancer cells at significantly lower doses than those required to harm healthy cells.

In other words, the compounds selectively targeted cancer cells while sparing normal ones. Such a finding is key to demonstrating their potential therapeutic viability.

CBD and THC were also synergistic in the study. When used in a 1:1 ratio with each other, they were more effective than when used independently. This type of synergy between cannabinoids has been noted in other areas of medical research and is often referred to as the “entourage effect.”

Prior to their work, the researchers noted that the exact mechanism through which THC and CBD elicited their anticancer effects was not clear, but their investigation identified several cellular effects that may help explain these findings, including:

• Reducing cancer cells’ “clonogenic potential,” or their ability to divide and regrow.
• Triggering apoptosis, programmed cell death, in roughly 25% of cancer cells.
• Decreasing metastatic potential, or the cancer cells’ ability to spread.
• Inhibiting key signaling pathways involved in cell growth.

“CBD and THC appear to inhibit the expression of key proteins within one of these pathways, thereby slowing down or blocking the pathway’s activity. By suppressing this cancer-promoting signaling, CBD and THC help reduce the growth and survival of ovarian cancer cells,” Tong said.

Implications for ovarian cancer treatment

Though these findings are promising, researchers would need to conduct extensive studies in animals and, eventually, in humans before any therapy could be approved.

Nonetheless, Tong asserts that these cannabis-derived compounds could one day make for promising adjunct therapies to treat ovarian cancer.

“It is likely that CBD and THC would be used alongside standard chemotherapeutic agents. They may help reduce chemoresistance in difficult-to-treat cases while exerting their own anti-tumor effects. Additionally, because CBD and THC have known benefits such as anti-inflammatory, anti-nausea, and analgesic properties, they may also improve patients’ quality of life during treatment,” Tong said.

Ovarian cancer is the second most common gynecological cancer in the United States and results in more deaths than any other cancer of the female reproductive system. Approximately 20,000 cases were estimated, and more than 12,000 deaths were attributed to it in 2025.

This form of cancer can be difficult to diagnose, with individuals often presenting with non-specific symptoms, resulting in late-stage diagnosis and worse outcomes.

For Ratner, a clinician who manages ovarian cancer patients and routinely utilizes medical marijuana for symptom relief, research into new therapeutic possibilities is exciting.

“The key to treatment in oncology right now, at least in my hands, is to allow women to live their lives while I’m taking care of the cancer,” she said.

“There is really almost no toxicity with cannabis, and it has great benefits for symptom management. So, if there are additional benefits in terms of cancer biology, that would be amazing.”