St. John’s University student Taylor Healey was puffing on an e-cigarette one night in February when she suddenly became violently ill.

Healey, 21, said she’d taken between 25 and 35 puffs of a mint-flavored Juul pod while hanging out with friends near the school’s Jamaica, Queens, campus when her mouth started to water and her body became drenched with sweat.

“I started vomiting like I never have before, and have never felt that kind of pain before while getting sick,” Healey, an accounting major, told The Post.

She’s one of hundreds of people nationwide who’ve confounded doctors with mysterious illnesses apparently related to vaping in the midst of a crisis that’s already claimed six lives, sent another 380 people across 36 states to the hospital and spurred a temporary federal ban on flavored e-cigarettes by President Trump that will be implemented in the next couple of months.

But doctors are still scrambling to identify the root cause of the problem — leaving users terrified they could be next.

“We’re the guinea pigs for this. We’re the test dummies,” said Healey. “We have no clue what this could cause and we’re gonna have to live with it someday.”

In New York, doctors have already recorded a total of 64 patients since June who’ve become sick after vaping, including 14 in the five boroughs and another 17 in the greater metropolitan area.

Dr. Jorge Mercado, the director of pulmonary bronchoscopy at NYU Langone Brooklyn, has treated two of them — but says he still doesn’t know exactly what’s causing the problems.

“We have put all the data together and this is more than just a trend, it’s almost like an epidemic,” Mercado told The Post.

“I think most of the physicians are trying to assert why this is happening and is it the substances? Is it the combination? Is it the marijuana? We really don’t know.”

There is no evidence to this point conclusively linking flavored products to the illnesses.

The New York State Department of Health has been careful about answering questions on what type of vaporizers have made people sick, citing an “ongoing investigation,” but says it is looking at illegal marijuana vapes, which could be laced with any number of cutting agents.

State officials tested the vapes that patients were using and found “nearly all” of the cannabis-containing samples showed “very high levels” of vitamin E acetate, making it a “key focus” of the department’s investigation, according to a DOH press release.

While a relatively harmless ingredient, vitamin E acetate can cause respiratory issues because of its oil-like properties, the department said.

Gov. Andrew Cuomo has sent subpoenas to three companies that market thickening agents to manufacturers of vape liquids. The thickeners are readily available online and are billed as a “cheaper, safer alternative … that can be used to cut vape products to any level of THC,” according to the DOH. It tested samples of the thickening products and found all three are nearly pure vitamin E acetate oil.

Still, the national Centers for Disease Control and Prevention has cautioned against pointing a finger at any one ingredient, including vitamin E acetate.

The CDC, which previously reported 450 possible cases, narrowed that number down to 380 confirmed or probable cases last week. It said the majority of patients used marijuana oil vaporizers and only a “smaller group” reported using nicotine only.

But there’s a reluctance from some patients, especially those who are underage, to disclose to their doctor what exactly they’re vaping, especially if it’s recreational marijuana.

Mercado said he asked the two young men he treated if they were using marijuana or nicotine vaporizers and “didn’t get a good answer.”

Another issue is a lack of regulation of e-cigarettes currently on the market.

When vapes first rose to popularity under President Barack Obama’s administration, they seemed like a safer alternative to cigarettes and were allowed to be sold without oversight from the Food and Drug Administration, Department of Health and Human Services officials said.

The FDA didn’t gain the right to oversee the products until 2016 — when countless options had already flooded the market, but none had been tested or were subject to any regulatory oversight. The Trump administration will finally implement a mandatory public health review over the next couple of months.

Finally, counterfeit Juul products continue to be a huge problem for the vape behemoth, which accounts for 70 percent of the e-cigarette market.

When Juul pulled all of its flavored products off the shelves in November 2018, bogus options from China began popping up. Juul’s online enforcement team reports more than 300 counterfeit listings for removal per week, or more than 15,000 per year, the company told The Post.

When asked about Healey’s recent sickness, Juul’s New York rep Austin Finan said in a statement it couldn’t confirm if the pod she smoked was counterfeit or legit.

Until the CDC is able to sift through the cases and figure out what exactly is causing these illnesses, it has advised everyone to exercise caution when vaping and to never purchase products off the street or from third-party resellers.