HILDALE, Utah (AP) – The tea tasted bitter and earthy, but Lorenzo Gonzales drank it anyway. On that frigid night in remote Utah, he was hoping for a life-changing experience, which is how he found himself inside a tent with two dozen others waiting for the psychedelic brew known as ayahuasca to kick in.

Soon, the gentle sounds of a guitar were drowned out by people vomiting—a common downside of the drug. Some gagged; several threw up in buckets next to them.

Mr. Gonzales started howling, sobbing, laughing and repeatedly babbling “wah, wah” like a child. Facilitators from Hummingbird Church placed him face down on the grass, calming him momentarily before he started laughing and crawling on all fours.

“I seen these dark veins come up in this big red light, and then I seen this image of the devil,” Mr. Gonzales said later. He had quieted only when his wife, Flor, put her hand on his shoulder and prayed.

His journey to this small town along the Arizona-Utah border is part of a growing global trend of people turning to ayahuasca in search of spiritual enlightenment and an experience they say brings them closer to God than traditional religious services. Many hope the psychedelic tea will heal physical and mental afflictions after conventional medications and therapy failed. Their problems include eating disorders, depression, substance use disorders and PTSD.

Ayahuasca is a psychedelic brew whose roots go back hundreds of years to ceremonial use by Indigenous groups in the Amazon region.

It is widely used in South America where it is legal in several countries, including Peru and Brazil. But in the United States, it remains illegal because the brew contains the psychedelic N, N-Dimethyltryptamine or DMT.

Despite its illegal status, ayahuasca has become increasingly popular in the U.S., and interest has intensified as celebrities like NFL quarterback Aaron Rodgers and Hollywood star Will Smith talked about attending ceremonies.

The rising demand for ayahuasca has led to hundreds of churches like the one described above, which advocates say are protected from prosecution by a 2006 U.S. Supreme Court ruling. In that case, a New Mexico branch of a Brazilian-based ayahuasca church won the right to use the drug as a sacrament—even though its active ingredient remains illegal under U.S. federal law. A subsequent lower court decision ruled Oregon branches of a different ayahuasca church could use it.

“In every major city in the United States, every weekend, there’s multiple ayahuasca ceremonies. It’s not just a twice-a-year thing,” said Sean McAllister, who represents an Arizona church in a lawsuit against the federal government after its ayahuasca from Peru was seized at the port of Los Angeles.

But with the growth of pro-psychedelics movements has come increased scrutiny. In addition to ayahuasca shipments from South America being seized, some churches stopped operating over fears of prosecution. There are also concerns these unregulated ceremonies might pose a danger for some participants and that the benefits of ayahuasca haven’t been well studied.

“Our knowledge is kind of limited,” said Anthony Back, a professor at the University of Washington School of Medicine in Seattle. “There is not as much information about safety as the regular other medical treatments that you might get if you went to a regular doctor in the United States.”

It was dark as the Hummingbird ceremony began on a Friday night in October, except for flickering candles and the orange glow of heaters. Psychedelic art hung from the walls; statues of the Virgin Mary and Mother Earth were positioned near a makeshift altar.

A mix of military veterans, corporate executives, thrill seekers, ex-members of a polygamous Mormon sect and a man who supposedly struck it rich on a game show had converged for the $900 weekend. Many appeared apprehensive yet giddy to begin the first of three ceremonies.

They sat silently, awaiting the arrival of Taita Pedro Davila, the Colombian shaman and traditional healer who oversaw the ceremony.

The brew contains an Amazon rainforest shrub with the active ingredient DMT and a vine containing harmala alkaloids that prevent the drug from breaking down in the body.

Those who drink ayahuasca report seeing shapes and colors and going on wild, sometimes terrifying journeys that can last hours. In this dreamlike state, some say they encounter dead relatives—one woman saw family members who had died in a car accident—as well as friends and spirits who talk to them.

“When you were invited here, you were invited for a weekend of healing,” Mr. Davila told the group in Spanish through a translator, before people lined up for shot glass-sized doses of the thick, dark tea in plastic cups.

Mr. Davila, wearing a fedora, a boar-tooth necklace and beaded chest plate with a jaguar image, locked eyes with each participant, uttered a prayer over the cup, blew on it with a whistling sound and handed it over. After everyone drank and was settled on mattresses, Mr. Davila strolled through the tent as the drugs took hold, shaking a bundle of leaves and playing a mournful tune on the harmonica.

“Every process is an individual one and completely different for every one of us,” he said. “We are going to turn off our minds and open our hearts. If you feel like you are dying, die. This is going to allow you to be reborn.”

Mr. Gonzales and his wife, Flor, were among several ayahuasca newcomers.

They had driven from California, hoping for relief for Gonzales. He’d battled drug addiction for much of his 50 years, was suffering the effects of COVID-19 and had been diagnosed with early-stage dementia—likely a result of concussions over the years, one from a motorcycle crash and another from an industrial accident. He doesn’t drive due to memory loss, rarely sleeps and is prone to angry outbursts.

“My poor body is dying and I don’t want it to die,” Mr. Gonzales said.

Flor Gonzales, 48, had grown weary of doctors and the pills they prescribed. None of it worked and she feared losing Lorenzo. So she researched ayahuasca and figured it was worth trying.

“If he’s already sick and he’s been placed on all these medications that have side effects, what do we have to lose?…It might stop the progression of the illness,” she said. “It might help him…accept things more without the anger.”

Maeleene Jessop was also an ayahuasca newcomer but was intimately familiar with Hildale, the Utah town where the ceremony was held. She’s a former member of the Fundamentalist Church of Jesus Christ of Latter-Day Saints, or FLDS, a polygamist offshoot of The Church of Jesus Christ of Latter-Day Saints.

The ceremony was held in a tent on the grounds of a house owned by a former FLDS member in Hildale, where Ms. Jessop grew up, enduring sexual and physical abuse in the group’s stronghold. Ms. Jessop left the church after its leader, Warren Jeffs, was arrested for sexually assaulting girls he considered brides. He is serving a life sentence in federal prison.

The 35-year-old woman has struggled to adapt to life after the FLDS, which controlled almost everything from what she ate to what she wore. Since leaving, she has tried anti-depressants, therapy and other psychedelics like mushrooms to deal with depression and a range of physical ailments, including hearing and vision problems she blames on the abuse she suffered.

“I felt like I needed something more, like I needed a stronger breakthrough. So this is the next step,” she said of ayahuasca. “Hopefully it’s the last step.”

She remains wary of organized religion, but felt like Hummingbird offered what she was looking for—a sense of community and freedom to connect “to a higher power, whether that’s us or the universe or God, whatever you want to call it.”

More than three months after the ceremony, Ms. Jessop said she credits ayahuasca with easing her depression and improving her focus. She says she found some clarity about her life goals and plans to study communications to help her speak out about abuse.

Ayahuasca’s roots go back hundreds of years in the Amazon. In the past century, churches sprouted up in South America where ayahuasca is legal. Some Brazilian churches are a mix of Christian, African and Indigenous influences.

The movement found a foothold in the United States in the 1980s and interest has intensified more recently.

Some people spend thousands of dollars taking ayahuasca at five-star retreats in the Amazon. In the U.S., the movement remains largely underground, promoted by social media and word of mouth. Some ceremonies occur at supporters’ homes, Airbnb rentals and remote areas to avoid law enforcement scrutiny.

Like many of these, Hummingbird won’t be mistaken for a traditional Western church.

It has no written text and relies primarily on Mr. Davila’s prayers, chants and songs, in Spanish and the language of the Kamentsa people, to guide participants. Mr. Davila follows traditions he learned from his grandfather in Colombia, spending several days preparing the ayahuasca.

Before serving the tea, Mr. Davila conducts cleansing rituals—like blowing tobacco snuff up some participants’ noses to heighten its effects.

Courtney Close, Hummingbird’s founder who credits ayahuasca with helping her overcome cocaine addiction and postpartum depression, believes the designation as a church helps show that participants are “doing this for religious reasons.” But when it comes to defining it as a religion, Ms. Close stresses much depends on individual participants’ experience.

“We just try to create a spiritual experience without any dogma and just let people experience God for themselves,” said the 42-year-old, who participated in about 200 ceremonies and had a vision to start the church at one of them.

Since holding the church’s first ceremony in Joshua Tree five years ago, Ms. Close has seen Hummingbird’s numbers grow and its demographic change—mostly from young hipsters to older, working-class people desperate for mental health treatment.

The most jarring moments have been people talking openly about suicide and viewing ayahuasca as their only hope. She recalled a sex crimes investigator and combat veteran who was so depressed he couldn’t speak without crying and told her: “If this doesn’t work, I’m killing myself.”

Ms. Close said Mr. Davila offered the man ayahuasca and then said to wrap him in a blanket on his side so he wouldn’t choke on his vomit. She hoped the psychedelic would provide him with a transformative, death-like experience while remaining physically safe.

“After the weekend, he looked like a different person where I was like, ‘Oh my God. Like, this guy is smiling and talking to people,’ “she said.

But Ms. Close knows ayahuasca comes with risks, especially when inexperienced users focused on making money start hosting events.

“That’s so dangerous,” she said, recounting instances of people at ceremonies being sexually assaulted, ripped off and sent home without follow-up support.

To improve safety, Hummingbird has brought doctors, nurses and CPR-trained staff to ceremonies, encouraged participants to stop taking certain medications before they arrive, and created an intake process that weeds out those with severe mental illnesses and some heart conditions. They implemented a no-touching policy during ceremonies and stopped offering other psychedelics.

But Ms. Close worries a U.S. government crackdown is coming, given the presumption the largely unregulated movement is “an epidemic of psychedelic churches that are creating a public health crisis.”

Back in California, Flor Gonzales is convinced the drug is behind Lorenzo’s improvement.

“The ayahuasca changed him in a lot of ways,” she said. “We’re more optimistic about the future.”

The father of four said he has stopped taking pills for depression, PTSD and insomnia. He still has moments of forgetfulness and doesn’t drive, but says he sleeps through the night and his screaming fits are a thing of the past.

“I feel healthier,” he said. “I feel like a dark force has been taken out of my soul.”