Chinitz came to this unusual treatment after years of seeking relief for her son. When Alex was a child, his chronic inflammatory bowel disease (IBD) was so debilitating that he was dependent on steroids to keep it in check; he took six different medications at one point. He often isolated himself, preferring to sit alone in his sensory swing than to spend time with others.

Improvement in his gut health came when Alex was nearly 10, after his mother changed his diet, cutting out grains and processed sugars. But she was intrigued to see whether helminths might have an even greater effect.

She first read about “helminth therapy” in 1999, when Alex was 5, in a news article. “It still hangs in a frame above my desk,” she says. But it took her years to figure out how to procure the worms. Helminths are not exactly stocked in pharmacies, and their manufacture, distribution, and importation is illegal in the United States. Eventually, though, when Alex was 13, she found a Thai supplier, now called Tanawisa. She spent $6,000 on a six-month supply of Trichuris suis ova—eggs of whipworms that typically live in pigs—and took a risk having them shipped to her home in New York.

Alex began ingesting about 2,500 invisible eggs in a small drink every two weeks. About 14 weeks later, Chinitz says, she noticed that her son no longer wanted to be by himself. It was like a “happy pill,” she says. “He was responding so beautifully to it, I went into a panic because I couldn’t afford to keep it up.” And so began their journey with helminths.

Despite her conviction, there’s no proof that these treatments work. A colonoscopy has shown that Alex’s IBD is in remission, Chinitz says, but there’s no evidence of any change to his brain; as for his behavior, he may have felt more social after ingesting the whipworm eggs, simply because his stomach hurt less. Anecdotally at least, his story resonates with many others who report relief from some autism traits after helminth therapy. In a 2017 survey of physicians monitoring 700 helminth users, more than half of the users have autism and the majority have had a favorable response, says William Parker, a researcher at Duke University in Durham, North Carolina, who led the survey. “The helminths are definitely helping some of the kids.”

Proponents of the approach offer this as a biological rationale: Treatments that shake up the balance of organisms in the gut are known to affect the brain. Almost 20 years ago, for example, researchers noticed that antibiotics could bring about short-lived improvements in autistic children who had lost their language abilities and social skills. I take parasitic worms for my ulcerative colitis, a form of IBD. A regular influx of hookworms seems to keep my disease in remission, but I previously tried Trichuris suis to no effect.