Cannabinoids could enhance the effectiveness of chemotherapy treatments while simultaneously reducing their side effects, according to a new study published in the journal Pharmacology & Therapeutics.
In a comprehensive review of existing research, researchers from the Institute of Pharmacology and Toxicology at Rostock University Medical Center, Germany, examined the growing body of preclinical and clinical evidence on medical cannabis interactions with various anticancer treatments.
The analysis revealed that when combined with chemotherapy, cannabinoids appear to help kill cancer cells more effectively than chemotherapy alone, sometimes making the treatments work together in ways that are more powerful than just their individual effects added up, especially in glioblastoma, haematological malignancies, and breast cancer.
“The data available to date raise the prospect that cannabinoids may increase the efficacy of chemotherapeutic agents while reducing their side effects,” the researchers said.
The study also highlighted cannabinoids’ potential to alleviate chemotherapy-induced side effects beyond the already established benefits for nausea and vomiting. Recent preclinical studies suggest cannabinoids may also help reduce side effects such as peripheral neuropathy, nephrotoxicity, cardiotoxicity, cystitis, bladder complications, and mucositis.
Cannabis is already used to treat chemotherapy-induced nausea and vomiting, as well as tumour-related pain. Many cancer patients also self-administer cannabis during treatment, both with and without medical prescriptions, the researchers noted.
The authors also highlighted how most current lab studies only examine how cannabinoids and chemotherapy kill cancer cells directly, emphasising the need for more research into other important aspects, such as how these combinations affect the immune system, blood vessel formation in tumours, and cancer’s ability to spread to other parts of the body.
“An equally thorough investigation of the effects of such combinations on the immune system and on the tumorigenic levels of angiogenesis, invasion, and metastasis is still pending,” the researchers wrote.
The findings follow on from another large-scale analysis, published in April 2025, which revealed overwhelming scientific support for the use of medical cannabis in cancer treatment.
This study analysed data from over 10,000 peer-reviewed research papers, finding that more than 70% of studies support the therapeutic benefits of cannabis for cancer patients.
