The US Food and Drugs Administration has issued letters to manufacturers of cannabis-infused products promoted as having health benefits, warning them that their claims are untested and must be modified.

Warning letters have been sent to five companies regarding 18 products, which claim to have healthcare benefits that would require them to be registered as drugs under the Food, Drugs and Cosmetics Act 1906. Furthermore, the FDA discovered that many of the products did not actually contain any active cannabis-based ingredients.

The list of firms included brands such as Hemp Oil Care and Natural Organic Solutions, which sell cannabis-infused “products for therapeutic healthcare purposes.”

The letters require each company to remove claims on its website, packaging and marketing material that the products can improve health or prevent disease and illness.

The companies have been given 15 days to comply or could face enforcement consequences, according to FDA rules.

One of the firms to have received a warning, Canna Companion, which produces cannabis-based capsules that were said to reduce cancer symptoms in dogs and cats, has now removed therapeutic claims and testimonials from its website.