Cannabis could be used to reduce tumour growth in cancer patients, scientists have said.
New research reveals the drug's main psychoactive ingredient - tetrahydrocannabino (THC) - could be responsible for its success in shrinking tumours.
It is hoped that the findings could help develop a synthetic equivalent with anti-cancer properties.
But researchers warned that cancer sufferers should not be tempted to self-medicate.
Dr Peter McCormick, from the University of East Anglia's (UEA) school of pharmacy, said THC's anti-cancer properties have been known for some time but the study had identified the receptors responsible for fighting tumours.