Score one for Gwyneth Paltrow: The actress, often criticized for pushing some eccentric (and some say questionable) health practices, may not have steered her fans wrong when she recommended oil pulling for cleaner teeth.

Oil pulling is an ancient Indian technique for cleaning teeth and freshening the breath. It calls for swishing a teaspoon of sesame, sunflower or coconut oil around in the mouth for 20 minutes and then spitting it out. Proponents claim this remedy, part of the Ayurvedic system of medicine developed thousands of years ago, does everything from clearing up skin to preventing Alzheimer’s disease. But most advocate it for whitening teeth and cleaning the mouth. And on that last score, they appear to be on to something. Scientific evidence suggests that oil pulling can kill streptococcus mutans, the bacterium that causes cavities, bad breath and gum disease.

"There is some evidence that oil-pulling could be helpful in reducing the plaque index and the bacterial burden in the mouth," said Lyla Blake-Gumbs, MD, of the Cleveland Clinic's Center for Integrative Medicine in a recent news release.

Related: What’s the Safest, Most Effective Way to Whiten Your Teeth?

A small study published in an Indian journal of preventive dentistry compared children who practiced oil pulling with a control group of kids who used an antibacterial mouthwash. The researchers found that both the mouthwash and oil pulling were effective in killing S. mutans bacteria.

A second study using gold-standard research techniques found that oil pulling reduced the levels of bacteria, plaque and gum disease among teens. In a third study, oil pulling was found to be effective against S. mutans and several other harmful mouth germs.

A Canadian researcher also completed a recent study showing that oil pulling worked better than chlorhexadine, a powerful antiseptic use to treat gum disease.

“I was blown away by how the counts of S. mutans dropped,” says the University of Toronto’s Leslie Laing Dibbard, PhD, DDS, of her unpublished research on the effects of oil pulling in a small group of people with chronic dry mouth, a strong risk factor for oral disease and cavities.

Her subjects, all of whom had Sjogren’s syndrome, an autoimmune disease that attacks moisture-producing glands, saw their mouth bacteria levels drop between 10- and 100-fold after three weeks of oil pulling with virgin coconut oil (VCO). “What was even more amazing was that yeast [candida, a fungus] counts were down, in some patients by as much as 100-fold,” she says. “Yeast is very difficult to get rid of without an antifungal drug, which has a lot of side effects."

Related: 6 Surprising Way to Brush Your Teeth Better

There were other benefits. Her patients reported that their gums no longer bled after they flossed. and their teeth looked brighter. “I would not us the word, as Gwyneth Paltrow put it, ‘whiter,’" says Laing Gibbard. “The teeth of people with dry mouth look like they’re a dull ‘matte’ finish, and the coconut oil left their teeth looking glossy.” Some regained the ability to taste; others no longer had to get up in the middle of the night for a sip of water to lubricate their mouths.

The patients used a full teaspoon of VCO, but if you don’t have dry mouth, she says, take a half teaspoon of oil — it’s solid at room temperature — and let it sit in your mouth until it melts. Then swish it all around your mouth and through your teeth for 20 minutes, twice a day. “It can have a grainy texture and when you first do it it can seem, I’ll use the word, ‘grotty,’” she says, laughing. “You’ll get over it after the first or second day.”

Related: 7 Ways to Prevent and Treat Bad Breath

Make sure you don’t swallow the oil — it’s full of that S. mutans bacteria. But don’t spit it in the sink, either. The oil will return to its solid state and clog the drain. “Spit it into another receptacle and rinse your mouth with a little warm water so you don’t get oil on your toothbrush when you brush,” suggests Laing Gibbard.

And yes, you still need to brush and floss. “[Oil pulling is] not a replacement for brushing and flossing,” she says, “It’s an adjunct to those. That’s key.”

Denise Foley is a veteran health writer and a former contributing executive editor at Prevention magazine.