Doctors treating their coronavirus patients with Vitamin C - and say it is "significantly" improving their symptoms.
Hospitals in New York say individuals with Covid-19 that were treated with very high doses of the vitamin are doing much better than those that weren't
Despite this, experts are cautioning that the treatment is only experimental and there is currently no solid proof that Vitamin C can help beat coronavirus.
It comes as the coronavirus pandemic continues to affect thousands of people across the globe - with cases now reported in 183 countries.
Patients in New York are being given extremely high dosages of the vitamin as soon as they are brought to hospital, and then continue to receive high doses three to four times a day.
Dr Andrew Weber, a pulmonologist and critical-care specialist affiliated with two Northwell Health facilities on Long Island, said his intensive care patients with Covid-19 immediately receive 1,500 milligrams of intravenous Vitamin C.
They then continue on the same dosage multiple times a day.
"The patients who received vitamin C did significantly better than those who did not get Vitamin C," Dr Weber said.
"It helps a tremendous amount, but it is not highlighted because it's not a sexy drug."
Each dose is more than 16 times the National Institutes of Health's daily recommended dietary allowance of Vitamin C - which is just 90 milligrams for adult men and 75 milligrams for adult women.
Both the NHS and the World Health Organisation (WHO) say the only way to protect yourself from contracting the virus is to practice good hygiene and rigorously wash your hands.
A spokesman for Northwell, which operates 23 hospitals, said that Vitamin C was being "widely used" as a coronavirus treatment throughout the system, but pointed out that it varied from patient to patient.
Spokesman Jason Molinet said about 700 patients are being treated for coronavirus across the hospital network, but it's unclear how many are getting the Vitamin C treatment.
The Vitamin C is administered in addition to such medicines as the anti-malaria drug hydroxychloroquine, the antibiotic azithromycin, various biologics and blood thinners, Dr Weber said.
As of Tuesday, New York hospitals have federal permission to give a cocktail of hydroxychloroquine and azithromycin to seriously ill patients on a "compassionate care" basis.
President Trump tweeted that the unproven combination therapy has "a real chance to be one of the biggest game changers in the history of medicine".
Weber, 34, said Vitamin C levels in coronavirus patients drop dramatically when they suffer sepsis, an inflammatory response that occurs when their bodies overreact to the infection.
"It makes all the sense in the world to try and maintain this level of Vitamin C," he said.
Scientists in China are also carrying out tests to find out the effects of vitamin C on the new coronavirus.
But the dosage being tested is around 60 times the NHS daily recommended amount.
Researchers at the Zhongnan Hospital of Wuhan University are giving 120 patients with the virus 24g of vitamin C every day for seven days.
The results are yet to be published and experts say we won't know its effectiveness for some time.
Despite this, nutritionists are urging people to eat more fruit and vegetables, which contain Vitamin C, to boost their immune system during lockdown.
Jane Clarke, Dietician and Founder of Nourish said: "One reason fruit and vegetables are so loved by nutritionists is that they're packed with vitamins and minerals that are essential for the body's immune system to function effectively.
"Vitamin C is well known as a cold and flu fighter but because it is water-soluble, it can't be stored in the body.
"The best approach is to include fresh fruit and vegetables as part of your daily diet.
"If eating a lot of fibre is an issue, then try cooking them to make them easier to digest. Soups are a great source of vitamins, minerals and fibre."