High-dose vitamin C can boost the cancer-killing effect of chemotherapy in the lab and mice, research suggests.
Reporting in Science Translational Medicine, they call for large-scale government clinical trials.
Pharmaceutical companies are unlikely to run trials, as vitamins cannot be patented.
Vitamin C has long been used as an alternative therapy for cancer.
In the 1970s, chemist Linus Pauling reported that vitamin C given intravenously was effective in treating cancer.