A video ad previously pulled by animal rights group PETA is back and enraging online communities by promoting a supposedly scientific link between dairy products and autism.

The ad urges parents of children with autism to consider going vegan to “alleviate the devastating effects of autism”.

Fear mongering: One of PETA's controversial autism ads. Credit:PETA

“More research is needed, but scientific studies have shown that many autistic kids improve dramatically when put on a diet free of dairy foods”.

Vicki Gibbs, a clinical psychologist at Australia's largest non-profit, autism service provider, Autism Spectrum Australia told Fairfax Media the strength of PETA’s statement was concerning.