Laboratory studies have found that a combination of THC and CBD can kill ovarian cancer cells without harming healthy cells.
Researchers are exploring whether future cancer treatments could be developed from compounds found in cannabis. In laboratory experiments, a team studying two cannabis derived chemicals found that both were able to limit the growth of ovarian cancer cells.
Although extensive testing is still needed before any patient-ready therapies can be developed, the results highlight a potential path toward new treatments for a disease that is often detected late and remains difficult to manage.
“Ovarian cancer remains one of the deadliest gynecological malignancies, characterized by late diagnosis, high recurrence rates, and limited effective treatment options,” said Dr Siyao Tong of Khon Kaen University, lead author of the article in Frontiers in Pharmacology. “Our goal is to find alternative drugs that can improve efficacy and potentially reduce toxicity, ultimately bringing new hope to patients facing this challenging disease.”
A deadly illness
Ovarian cancer causes more deaths than any other cancer affecting the female reproductive system. While treatment approaches have improved over time, current medications can fail to control the disease and often produce serious side effects, underscoring the need for safer and more effective options.
Because CBD (cannabidiol, which is not psychoactive) and THC (delta-9-tetrahydrocannabinol, which is) have demonstrated anti-cancer activity in other studies, the researchers set out to examine their effects on ovarian cancer cells.
To do this, the team worked with two ovarian cancer cell lines. One line responds to platinum-derived chemotherapy, while the other is resistant to it. The cells were exposed to CBD, THC, or a combination of both to evaluate whether they could continue to survive and multiply. A separate group of healthy cells was also tested to determine whether the compounds caused unintended damage.
They found that cells for both cancer lines, which had been treated with CBD or THC, formed fewer and smaller colonies of cells. Though both compounds worked to prevent cancer cells from reproducing, combining them gave particularly good results. And although neither compound alone killed a large proportion of cancer cells, a combination of the two was very successful. It’s possible that THC and CBD act on the cancer cells in different ways, and when used together, their effects are amplified.
“Notably, the inhibitory effect was most pronounced when CBD and THC were used in a 1:1 ratio,” said Tong.
Additional assays showed that the compounds prevented cells from migrating, which means they might be able to stop ovarian cancer from spreading to other parts of the body. Many patients die of metastases, so a treatment that prevents metastasis could save lives.
Both cell lines were similarly affected, suggesting that the compounds could work equally well for different types of ovarian cancer. The compounds and their combinations also had minimal effects on healthy cells, which suggests that patients might find treatments made from them less toxic and easier to tolerate than current drugs.
To understand the mechanism behind these anti-cancer effects, the scientists looked at cell signaling pathways. The PI3K/AKT/mTOR pathway is overactivated in ovarian cancer cells, which contributes to tumor development and treatment resistance. The CBD and THC compounds seemed to restore normal regulation of the pathway, which could explain why the cancer cells couldn’t reproduce and began to die off after treatment.
Looking to the future
But much more work remains to be done before these results can be translated into practical treatments. The scientists call for further research which can establish if and how these compounds can be used as effective new ovarian cancer therapies.
“Although our study is still preliminary, it lays an important foundation for future research into the potential applications of CBD and THC in ovarian cancer treatment,” said Tong. “By confirming their anti-cancer activity and identifying key molecular mechanisms, our findings are expected to drive further preclinical research. If future studies confirm these effects, CBD-THC combination therapy may ultimately contribute to the development of new treatment strategies.”
“However, this study has some limitations,” Tong added. “All experiments were conducted in vitro, so the results may not fully reflect the complexity of tumor behavior in living organisms. We did not include in vivo models and pharmacokinetic data, which are crucial for determining whether CBD/THC can be safely and effectively used clinically. Finally, regulatory and legal issues surrounding cannabinoid therapy may also affect future translational research. While the results are encouraging, more studies are needed before these findings can be applied to patient treatment.”
Reference: “Selective anti-cancer effects of cannabidiol and Δ9-tetrahydrocannabinol via PI3K/AKT/mTOR inhibition and PTEN restoration in ovarian cancer cells” by Siyao Tong, Watcharin Loilome, Nisana Namwat, Poramate Klanrit, Arporn Wangwiwatsin, Zar Zar Win, Preeya Koyabuth and Bandit Chumworathayi, 20 October 2025, Frontiers in Pharmacology.
DOI: 10.3389/fphar.2025.1693129
Funding: Khon Kaen University
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