Investigators at Italy's Instuto di Chemica Biomolecolare assessed the anti-cancer activity of various non-psychoactive cannabinoids - including cannabidiol (CBD), cannabigerol (CBG), and cannabichromine (CBC) - in vivo and in vitro. Researchers reported that CBD acts as a more potent inhibitor of cancer cell growth than other cannabinoids, including THC, and noted that the compound is particularly efficacious in halting the spread of breast cancer cells by triggering apoptosis (programmed cell death).

Cannabigerol and CBC also possess anti-tumor properties, but lack the potency of CBD, they found.

"These results suggest the use in cancer therapy for cannabidiol," investigators concluded.

Previous studies have shown cannabinoids to reduce the size and halt the spread of glioma (brain tumor) cells in animals and humans in a dose dependent manner. Separate preclinical studies have also demonstrated cannabinoids to inhibit cancer cell growth and selectively trigger malignant cell death in skin cancer cells, leukemic cells, lung cancer cells, and prostate carcinoma cells, among other cancerous cell lines.