Will Smith, Megan Fox are praising psychedelics. What medical experts want you to know.

Ever heard of magic mushrooms? Or smoking a toad's venom? What about ayahuasca?

Psychedelics drugs have long been popularized by celebrities, and most recently a few big names spoke out about their experiences: Will Smith credited an ayahuasca trip in Peru to helping him find happiness, calling it "the unparalleled greatest feeling I've ever had," while former NBA athlete Lamar Odom is set to share his own experience with psychedelics as a headliner to a health, wellness and business event about psychedelics, Meet Delic.

Earlier this year, HGTV star Christina Haack claimed the hallucinogenic properties of a toad's venom reset her brain and "kicked out years of anxiety," and Megan Fox said psychedelic tea helped her in a way that "talk therapy or hypnotherapy" couldn't.

Some medical experts, citing clinical research, say there can be legitimate benefits to using psychedelic drugs in the proper quantities and in safe settings. But they also warn following the latest buzzed-about celebrity medical trend can dangerous.

The use of psychedelic drugs, even in medical settings, is illegal in the United States except in Oregon, which legalized psychedelic mushrooms in 2020.

"When people are stuck or suffering, well-guided change can be beneficial, and psychedelics are agents that encourage such transformative experiences," says Dr. Alex Dimitriu, who specializes in psychiatry and sleep medicine but does not use psychedelic treatments with his patients because the treatments are illegal.

He adds psychedelics can encourage users to "connect loose themes" and experience "improved lucidity and memory." But that does not mean they are for everyone or should be used recreationally.

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First, what is toad's venom? And ayahuasca?

Hallucinogens have been around for decades and have been a buzzy topic Hollywood before — think back to the Beatles' LSD usage. Recently, they've had a small resurgence in pop culture as more stars speak about using them, particularly lauding their therapeutic purposes.

Chelsea Handler got candid about her ayahuasca trip with a shaman in her show "Chelsea Does," and Lindsay Lohan shared her experience with the same psychedelic tea saying it allowed her to let go of "wreckage from my past."

Earlier this month, Haack made waves when she said she smoked a Bufo toad's venom in order to have a similar psychedelic experience.

The increasing popularity of psychedelics isn't surprising to Dr. Sameet Kumar, a clinical psychologist who specializes in helping people who have cancer, grief or end-of-life concerns. Kumar, who does not use the treatment with his patients due to its illegality, believes in the right doses and proper environment, these "agents of change" can allow a person to dive into their subconscious thoughts and address deep traumas.

Indeed, some research has shown psychedelic therapy has potential in treating mental health disorders: In 2020, a clinical trial conducted at Johns Hopkins University found that 71% of patients with major depressive disorder experienced a "clinically significant response" to psychedelic therapy treatments.

However, Kumar cautions that ayahuasca, specifically, is tricky to study. "It's a natural medicine so dosage hasn't been standardized yet to be studied in the U.S." (The participants in the clinical trial at Johns Hopkins received capsules with psilocybin, the compound found in magic mushrooms, and engaged in psilocybin-assisted therapy.)

Dimitriu notes this research doesn't mean that psychedelics will have a therapeutic effect on all users.

"Some people do report the psychedelic experience as a waking dream, which can be a beautiful, or nightmarish thing, depending on the ever important mindset and setting. This is where strong therapeutic support, before during and after is essential."

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Psychedelics must be used properly, and they aren't for everyone

Though celebrities are praising their psychedelic experiences, experts caution that it isn't a replacement for therapy. Haack said she hired a spiritual coach to guide her experience, while Fox said she prepared for hours to ensure she was trying ayahuasca in the "proper setting."

Dimitriu explains, "All of these psychedelic therapies aren't just giving people a drug then sitting back. They are done in a therapeutic process with hours of preparation and integration."

Kumar adds "it's a dangerous dichotomy to say there's psychotherapy vs. psychedelics — that it's one or the other."

These two things need to go hand-in-hand. But what makes psychedelics a promising form of treatment, he says, is their ability to "pull someone out of their comfort zone, especially for those who are resistant to doing so in standard talk therapies."

Still, there can be serious consequences to trying psychedelics: "You don't want to melt your brain with no direction, or form for it to solidify back to," Dimitriu says. "The best outcomes come from combining psychedelics with therapy, before, during, and after use — as this provides a form and guidance for the experience."

Plus, the experts say there are certain people who are at-risk for a negative experience, even with the proper setting and dosage, and they should avoid psychedelics.

Dimitriu says those experiencing psychological difficulties such as loss or trauma are more likely to benefit from psychedelic therapy than those with longstanding family histories of depression, anxiety or psychosis.

Anyone with any personal or family history of schizophrenia should steer clear of these substances.

"We don't want people prone to psychosis to use psychedelics, not because there's an inherent damage but because the research isn't there yet for that," says Kumar. "The same goes for bipolar disorder.

"They should also be used very cautiously as they may destabilize mood symptoms."

This article originally appeared on USA TODAY: Will Smith, Megan Fox tried ayahuasca, psychedelics. What to know