Fenfluramine treatment of twenty children with autism.

Doctors gave twenty autistic children fenfluramine pills for forty-eight weeks. They watched if the drug cut odd movements or raised IQ scores.

Half the kids got real pills first, then placebo. The other half got the reverse order. No one knew which pill was which until the end.

The drug only trimmed a few repetitive body motions. It did not lift test scores or help language.

After almost a year, the changes were too small to matter in daily life.

Meyer et al. (1987) looked at five kids two years earlier. They saw bigger drops in Valsalva-type breathing tics. The 1989 trial used tighter rules and found weaker gains, showing the first hopeful signs may have been luck.

Bent et al. (2011) and Jones et al. (2010) tested other oral pills—omega-3 and digestive enzymes—in similar double-blind styles. Like fenfluramine, those pills also left core autism symptoms unchanged.

Höfer et al. (2017) and Saral et al. (2023) report that up to nine in ten families still try non-Rx pills or diets. The old fenfluramine data warn that “natural” or “pill” does not equal “effective.”

When parents ask about supplements or old drugs, you can share this clear evidence: fenfluramine barely touched motor tics and did nothing for cognition or language. Use the data to steer families toward interventions with stronger backing—like ABA, speech, or sleep plans—and always check what else they are giving.