If diffusing basil is your new way to focus better at work, or you swear by a dab of clove on an achy tooth, you’ve been bit by the essential oils bug. Pop those bad boys in your bath, lotion, laundry, brownies—wait a minute. Did that last one cause a record-scratch sound effect in your brain, like it did for me? Sniffing and slathering are practically routine—but can you really ingest essential oils?

The answer, essentially, is: Yes but, maybe you shouldn’t. Safely ingesting certain essential oils is wrought with caveats and debate, and it’s not recommended without guidance from a trained herbalist. “The whole purpose of distilling the aromatic components [from plants] was because we wanted to capture their smell,” says Amy Galper, aromatherapist and co-founder of the New York Institute of Aromatic Studies. “We understood the power of aroma [to affect] our mind, our spiritual life, and our physical health.” Ingesting, therefore, is outside of boundaries of essential oils’ intended use—enough reason to proceed with caution.

So before you get drop happy, here’s what you need to know about ingesting essential oils.

Essential oils are incredibly potent when ingested…

If essential oils are made for their scent, why would anyone want to ingest them? Galper says people do it for “a more concentrated delivery” through digestion.

This is precisely why Yufang Lin, MD, an integrative medicine specialist at Cleveland Clinic, warns against swallowing essential oils. “I do love aromatherapy,” Dr. Lin says. But, “I usually caution people against taking it orally is because it’s a really strong medicine…You can take too much, too quickly without realizing it. And that can become toxic.”

…and can therefore be dangerous

Essential oils may be natural, but that doesn’t mean they’re inherently safe. “The molecules and chemical constituents that make up essential oils are irritating to mucous membrane tissue,” Galper says. Swallowing essential oils can burn the mucosa in your mouth, esophagus, gut lining, and beyond in the digestive tract. Dr. Lin says nausea, stomach pain and neurological discomfort like nerve pain and numbness can also occur, especially if you take too much. Like any kind of medicine, it can affect different people in different ways, too.

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Drinking drops of straight essential oil is a no-go

Just think: When you put them on your skin, you know to use a carrier oil to avoid irritation. Now consider the fact that our digestive tract is much more sensitive. “We have to have that same mindfulness if we’re going to swallow it,” Galper says.

Since water and oil don’t mix, diluting drops in water won’t work either—it’s just another one-way ticket to irritation. Instead, Galper says you can take one or two drops with a carrier oil, honey, or in capsules with MCT oil or vegetable glycerin, so the essential oil dissolves and won’t be damaging to your system. As for using them to flavor food, Dr. Lin says it’s likely okay if it’s a minute amount in a tested recipe (like one or two drops per two to three cups of food), but she still recommends exercising caution.

There are some “safe” oils, and others to avoid at all costs

The Food and Drug Administration (FDA) keeps a list of essential oils that are Generally Recognized As Safe, but this list isn’t gospel. The FDA also doesn’t regulate essential oils, which makes choosing one even trickier. Look for a brand void of additives from a company that’s transparent about where they grow their plants and how the oils are extracted.

Keep in mind, certain oils can be especially toxic and should never be swallowed, like tea tree, eucalyptus, and wintergreen. “Honestly, if you put a drop of anything on your skin and it would immediately make you itch, I would not eat it,” Galper says. She also avoids oils like cinnamon, thyme, and oregano.

Talk with a professional before trying it

Moral of the story: It’s possible to ingest essential oils safely, but it’s complex and should always be done under the guidance of a trained herbalist. “They should never just be dropped,” Galper says. A professional will know which oils are safe and work with you to administer correct, non-toxic doses. Your best bet? Fire up that diffuser…

Here are 10 essential oils to try if you’re looking to fight inflammation. And 4 with serious headache-fighting prowess.