Marijuana laws in the United States are changing almost daily. Right now, recreational marijuana is legal in eight states and the District of Columbia, and medical marijuana is legal in more than 30 states.

That's for people. What if you want to consider cannabis for your cat or dog? There's the whole question of legality plus the fact that there's little research, other than word of mouth, on whether it actually works. Yet you see the ads on social media, or the posts from your friends, promising that it will ease pain and anxiety for your pets. Maybe you're tempted to try it.

Here's a look at the somewhat murky world of cannabis for cats and dogs.

What's in a name

CBD oil CBD oil can be made from marijuana or hemp, both of which come from the cannabis plant. (Photo: ElRoi/Shutterstock)

Marijuana is classified as a Schedule I drug by the federal government, which means it's illegal because it has "no currently accepted medical use and a high potential for abuse."

But it's not marijuana, exactly, that people consider for their dogs and cats. When searching for a solution for pain and anxiety in pets, attention often turns to cannabidiol (CBD), a chemical compound derived from marijuana or from the closely related hemp. Both marijuana and hemp are varieties of cannabis sativa, a subtype of the cannabis plant. The main difference between the two is that marijuana has much more tetrahydrocannabinol (THC) than hemp. THC, another compound that comes from the marijuana plant, is what gets users high. Because CBD has little or no THC, it doesn't have that effect.

Some pet owners say CBD helps with all sorts of medical conditions from cancer to seizures, inflammation to nausea. CBD is available as oils, pills and in treats. It's most readily available online.

But, as Consumer Reports points out, CBD's legality lurks in a gray area. Because marijuana is classified as an illegal drug by the federal government and hemp's legal status isn't always clear, the sale of CBD can be controversial.

If you live in a state where medical marijuana isn't legal, then CBD oil derived from marijuana isn't legal either. The legality of CBD derived from hemp isn't so clear.

According to Veterinary Practice News:

Websites that market medicinal hemp products for use in companion animals may claim that hemp is legal across the United States. A look at summaries of state statutes on the National Conference of State Legislatures’ website suggests that laws regulating hemp differ among individual states. Eight states, including Colorado, have sponsored hemp resolutions and created laws "to promote the growth and marketing of industrial hemp." Some state policies, but not all, have explicitly excluded industrial hemp from the definition of controlled substances under state law. Even when such products are defined in these ways, the cannabis industry lacks sufficient regulatory oversight to ensure that products labeled as hemp contain low levels of THC.

At the state level, CBD is legal in some form in nearly every state (at least for people), but there are many caveats. Some states require a doctor's recommendation, and some only allow it for certain conditions.

"As long as there is conflict between federal and state law, there will continue to be confusion over the legal status of CBD," Amanda Reiman, Ph.D., a cannabis policy and public health expert who also works for Flow Kana, a cannabis company, tells Consumer Reports.

In June 2018, the U.S. Senate passed agricultural legislation known as the Farm Bill. Part of the bill includes provisions that legalize the cultivation, processing and sale of industrial hemp. But there's still uncertainty about whether that means CBD made from hemp will be unquestionably legal.

What about buying CBD online?

Both Melvin Patterson, spokesman for the U.S. Drug Enforcement Agency, and Paul Armentano, deputy director of The National Organization for the Reform of Marijuana Laws or NORML, told Consumer Reports they know of no cases where consumers faced legal penalties for buying CBD products online.

But does it work?

dog with cbd oil Anecdotal evidence from pet owners finds that CBD sometimes helps with pain and anxiety. (Photo: Cannabis Reports/Flickr)

If you determine that CBD products are legal where you live, is it worth trying them for your pet? That also depends, say the experts.

Although things are slowly changing, there's little scientific evidence to back the claims about CBD's potential positive uses.

"Because of its cloudy classification and constantly-shifting political winds, CBD creates a legal quagmire for anybody who wants to study or recommend its effectiveness as a medicine for animals," writes Colin Rigley in Preventive Vet. "To date, there have been no rigorous scientific studies published on marijuana, or even the non-psychoactive CBD, as a treatment for pets with arthritis, seizures, anxiety, or any other medical conditions. But that may soon (hopefully) be changing, as a few studies are either in the planning stages or underway."

For example, a team of researchers from Cornell University recently submitted a clinical study that suggests that 2 mg of CBD oil twice daily can help increase comfort and activity in dogs with osteoarthritis. The study is awaiting peer review.

Check any pet-themed message board and you won't have to search long for anecdotal evidence that CBD helps with various conditions. These pet owners will gladly tell their stories.

But ask your veterinarian and you may get a limited response. The uncertainty about efficacy, safety and legality is making many vets steer clear from even having a conversation about CBD.

"My position is the same as the [American Medical Association]'s," says West Hollywood, California, veterinarian Douglas Kramer, an advocate for marijuana's potential as a veterinary therapy. "We need to investigate marijuana further to determine whether the case reports I'm hearing are true or whether there's a placebo effect at work. We also need to know what the risks are."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

What you need to know about pot for pets
Trying to figure out what's legal and what might work when considering CBD for your pet is murky territory.