CBD may help prevent cancer from spreading, researchers at California Pacific Medical Center in San Francisco reported in 2007.

Cannabidiol stops cancer by turning off a gene called Id-1, the study, published in the journal Molecular Cancer Therapeutics, found. Cancer cells make more copies of this gene than non-cancerous cells, and it helps them spread through the body.

The researchers studied breast cancer cells in the lab that had high expression levels of Id-1 and treated them with cannabidiol. After treatment the cells had decreased Id-1 expression and were less aggressive spreaders.

In WEED, Gupta also mentioned a few studies in the U.S., Spain, and Israel that suggest the compounds in cannabis could even kill cancer cells