The US government has thrown its weight behind the earth-shattering claims thatcannabis kills cancer cells.

Everyone from hippies to conspiracy theorists and even several creditable scientists have previously argued that smoking or ingesting the herb can have medicinal benefits.

Cancer kills up to 20,000 people worldwide every day, according to global health estimates.

Health researchers for the US government claim that cannabinoids – the active ingredients in cannabis – can inhibit the illness by causing cell death and blocking key blood vessels needed by tumours to grow.

They say studies in mice and rats show cannabinoids may be able to kill cancer cells – while still protecting normal cells.

It was also suggested that cannabidiol can boost the effectiveness of chemotherapy – without any of the nasty side effects.

“A study in mice showed that cannabinoids may protect against inflammation of the colon and may have potential in reducing the risk of colon cancer, and possibly in its treatment.

“A laboratory study of delta-9-THC in hepatocellular carcinoma (liver cancer) cells showed that it damaged or killed the cancer cells. The same study of delta-9-THC in mouse models of liver cancer showed that it had antitumor effects.”