Cannabis Use Linked to Reduce Risk of Oral Cancer, New Meta-Analysis Finds

After reviewing thousands of participants across multiple case-control studies, the analysis found that marijuana use was associated with a reduced likelihood of developing oral cancer. It was conducted by researchers from more than a dozen universities, including Al-Zahrawi University College, INTI International University, and Zarqa University. The researchers followed standard systematic review procedures, pulling data from major medical databases through August 2025 and focusing exclusively on studies that confirmed oral cancer diagnoses through histology. In total, six case-control studies involving 4,686 oral cancer cases and 10,370 controls were included. When pooled together, the results produced an odds ratio of 0.659, suggesting a roughly 34% lower risk among marijuana users. The findings remained stable even after a series of sensitivity checks, which produced odds ratios ranging from 0.599 to 0.708.

The researchers also looked at whether things like how long someone has used marijuana, when they first started, or their gender made a difference. They didn’t find a clear pattern showing that more use leads to a bigger effect, but a few of the studies did show a noticeable protective link. Others didn’t show any effect at all, which is why the overall results varied.

Researchers also cautioned that, even though the numbers were statistically strong, the findings shouldn’t be treated as final. Different studies measured marijuana use in different ways, and some newer research has shown conflicting results. Because of that, the authors say much larger, long-term studies are needed to figure out whether marijuana itself truly lowers oral cancer risk or if the lower risk is connected to other factors in the people who took part in the studies.