Researchers from the University of Otago in Christchurch are looking into whether vitamin C helps or hinders cancer patients.
The natural remedy is popular with some cancer sufferers, who take extremely high doses.
Every day, Renee Wallace takes 1000 milligrams of Lypo-Spheric vitamin C. The extremely high dose, more than 10 times the daily amount recommended, is part of her fight against stage 3 bowel cancer.
"I don't seem to pick up bugs easily, so it's a positive for me, and it's proven to me that it does work," she says.
The ascorbic acid, known to help the body to heal, has been touted by some as a wonder drug for cancer, some even getting it pumped into their veins.
Now researchers at the University of Otago campus in Christchurch are looking at vitamin C in bowel cancer, to see whether it actually works.
Research Associate Professor Gabi Dachs says researchers know vitamin C has roles in very basic biochemistry in cells.
"We're trying to figure out what those roles are in cancer."
It follows early studies, which indicated tumours that were exposed to vitamin C were less aggressive. However, it needs further research, which has been funded by the Cancer Society.
Dr Chris Jackson of the Cancer Society says scientists are still working out the balance.
"There's evidence that vitamin C may be helpful in cancer; there's also some that it may be harmful, and what we need to know is the balance of benefits and side effects."
Renee Wallace, who has been through surgery and chemotherapy, believes the researchers will find proof it works.
"I'm hoping that it will find that vitamin C can help almost cure bowel cancer."
The study is set to take a year and the results will be eagerly awaited, the world over.