Marijuana kills cancer cells, says US government

Cannabis has been found to kill cancer cells in mice and rats, according to researchers from the US National Cancer Institute.

The institute, part of the US Department of Health, posted on its website that "laboratory and animal studies have shown that cannabinoids [the active ingredient in cannabis] may be able to kill cancer cells while protecting normal cells".

It added: "They may inhibit tumour growth by causing cell death, blocking cell growth, and blocking the development of blood vessels needed by tumours to grow."

Studies carried out on rodents found that cannabinoids could help make chemotherapy more effective and reduce the risk of breast, colon and liver cancer, the Daily Telegraph reports.

But researchers said that it is too early to tell whether the drug will have the same effect on humans.

"At this time, there is not enough evidence to recommend that patients inhale or ingest cannabis as a treatment for

cancer-related symptoms or side-effects of cancer therapy."

A spokesman for the Cancer Research UK charity said: "There isn't enough reliable evidence to prove that cannabinoids, whether natural or synthetic, can effectively treat cancer in patients, although research is ongoing around the world."