Scientists have produced a deadly poison inside cancer cells with a new method Japanese researchers at the Kingdom Research Institute have developed a new experimental method to fight cancer, in which carbon monoxide produced in cancer cells is used to produce anti-cancer compounds. This method instead of delivering toxic drugs directly to the whole body, activates the chemical reaction necessary to produce drugs inside cancer cells. Early tests on cultured cells showed that the technology could selectively create toxic compounds in cancer cells and prevent their production in healthy cells.