A New Zealand probiotic company is backing calls in the United States for greater regulation of the products.
Probiotics boost numbers of beneficial bacteria which fight off harmful microbes.
Researchers writing in the journal Science say the American Food and Drug Administration should set evidence based standards for health claims made about the products.
The scientist who helped found the New Zealand firm BLIS Technologies, John Tagg, says probiotics involve living microbes and can potentially pose a risk to consumers so greater regulation is appropriate.
"It's a rapidly expanding field. It's a field in which live micro organisms are delivered to humans," Professor Tagg says.
"What we need to ensure is that it is a health benefit and not a risk of disease or of other ill effects."
Probiotics also degrade over time, so clear standards are important, he says.
