New York hospitals are conducting a clinical trial on whether or not the common heartburn drug, famotidine, may be an effective treatment for the coronavirus. The idea came from evidence that Chinese patients who took the drug seemed to fare better than those who didn’t.

Dr. Kevin Tracey, president of Feinstein Institutes for Medical Research at Northwell Health, which runs 23 hospitals in the New York area, is orchestrating the trial of famotidine, which is the active ingredient in Pepcid, according to CNN.

“We don’t know if it has any benefits,” he said. “There are many examples in the history of medicine where a drug that was designed for one purpose turns out to have an effect in another disease.”

So far, 187 patients have enrolled in the clinical trial, and Northwell hopes to increase that number to 1,200, Tracey told CNN. He emphasized that the study subjects are receiving famotine intravenously in doses nine times higher than one would normally take for heartburn.

“You should not go to the drugstore and take a bunch of heartburn medicine,” he warned. The expert was cautious about revealing the trial because, according to Science Magazine, “If we talked about this to the wrong people or too soon, the drug supply would be gone.”

So far, several anecdotal cases here in the U.S. are encouraging. David Tuveson, director of the Cold Spring Harbor Laboratory Cancer Center, recommended famotidine to his 44-year-old sister, an engineer with New York City Hospitals, after speaking to Tracey.

According to Science Magazine, she had tested positive for COVID-19 and her lips were turning dark blue from lack of oxygen. After taking her first megadose of famotidine on March 28, her fever broke and her oxygen level retuned to normal. Five of her co-workers also had dramatic results.

Tracey cautioned that we need to wait for the trial results to see if famotidine works or not. He certainly doesn’t want people how don’t have heartburn to rush out to buy famotidine tablets, depleting the supply for those who need the medicine.

“That’s the reality of trying to do the right thing in a pandemic,” he told CNN. “It’s very, very hard.