It’s illegal to give marijuana to animals. But some pet owners willingly break this law because they swear it helps their ailing Fido or Fluffy, reports Substance.com.

One reason pot may actually help is because cats and dogs have receptors in their nervous systems that respond to the cannabinoids in marijuana just like humans. (Cannabinoids are the part of the pot plant that has medicinal benefits for humans.)

What’s more, although this is not scientific evidence, folks claim that pot has helped their pets get relief from a range of symptoms including appetite problems, cancer-related pain, separation anxiety, irritable bowel syndrome and feline immunodeficiency virus infection, among others.

But be that as it may, federal law is clear: Marijuana is still a Schedule I drug—in the same category as heroin—so vets can’t prescribe pot for pets.

For that to change, more animal research will have to be done. In fact, some researchers are preparing to study medicinal marijuana for animals in a controlled lab setting.

One vet, Narda Robinson, from Colorado State University’s Veterinary Teaching Hospital, started her research by soliciting stories from pet owners who use Canna-Pet and Canna Companion, two pet supplements used for pain relief that are made from hemp, a plant that’s closely related to pot.

But don’t expect this to change the law very soon—you know what they say about old dogs and new tricks.

Click here for the more about pending legislation on medicinal marijuana for humans.