If you’ve got stubborn acne, or you’re looking for an alternative to drugstore and prescription acne treatments, you might consider essential oils. They are plant chemicals extracted with steam from stems, roots, leaves, seeds, or flowers.

Plant extracts have a long history in traditional and folk healing, and are regularly studied in modern medicine for their fabled effects, including how they kill bacteria, one of the primary causes of acne.

What Causes Acne?

Acne starts when skin flakes and skin oil (sebum) clog your pores. The plugged up pore becomes a breeding ground for bacteria, especially Propionibacterium acnes (P. acnes) bacteria, and a pimple is born. Most acne can be treated by applying a topical bacteria-killing agent to the surface of your skin.

Several essential oils kill bacteria. The big winners against P. acnes are thyme, cinnamon, rose, and rosemary. These plants and their scents and flavors are no doubt familiar to you. You can buy them online or at a health food or herbal medicine store.

1. Thyme

In the kitchen, thyme’s delicate essence is often used to enhance pasta sauces and cooked potatoes. And in the laboratory, it’s been shown to be effective against the germs that cause eye infections in addition to acne bacteria. (Do not apply it to your eyes, though! Wait until science has come up with an ocular thyme solution.)

2. Rosemary

Also fresh from the herb garden is rosemary, the essential oil of which was shown in lab tests to cause severe damage to P. acnes. Food scientists have studied rosemary’s positive effect on the fungal growth that rots food during harvest and packaging. And you thought it was only good with lamb.

3. Cinnamon

It turns out cinnamon is good for more than just holiday baking and sprinkling on your latte. This extensively studied tree bark product has been reported to reduce menstrual pain and cholesterol levels. In addition to proven effectiveness against P. acnes, cinnamon has been shown to kill staphylococcal bacteria as well as E. coli.

4. Rose

Yes, roses, the flower of romance and English gardens, can get your face rose petal fresh — or at least pimple-free. Rose essential oil also fights E. coli, Staphylococcus, and other kinds of bacteria. In animal tests, it’s been shown to be effective at reducing liver damage caused by acetaminophen (Tylenol).

5. Tea Tree Oil

Tea tree oil won’t leave your skin smelling as good as roses (it has a piney scent), but it is useful for killing bacteria and fungi. It has been shown to reduce acne, but scientists aren’t certain if that’s because it kills P. acnes, or because it reduces swelling. If you don’t care for undiluted tea tree oil, it’s also used as an ingredient in many skin products

6. Oregano

The king of Italian herbs has a strong natural scent, too. It has been extensively tested and shows promise for treating conditions as varied as those caused by malarial parasites, cancer cells, and bacteria that cause hospital-acquired infections (MRSA is one such type). It hasn’t been proven against P. acnes, but oregano is anti-inflammatory, which means it might help reduce swelling.

7. Lavender

Animal testing has shown that lavender could help improve skin conditions. It’s also been proven as an antimicrobial, but the scientific community still doesn’t know if it fights P. acnes. This essential oil will at least make you feel relaxed and promote sleep.

8. Bergamot

Bright and citrus-scented, bergamot advocates say that the fruit’s essential oil can improve your mood as well as help your skin. It’s been shown to be an anti-inflammatory, meaning that it can reduce swelling and shrink pimples.

How to Use Essential Oils

Because essential oils are concentrated plant chemicals, they can be very strong. Read the directions before applying any essential oil to your skin — you might need to dilute it with what’s referred to as a “carrier oil,” usually an unscented plant oil. You could also dilute it with water.

Never put essential oils in or near your eyes. Even the vapors can be irritating. And don’t use essential oils on your newborn’s baby acne (or anywhere on baby). Those tiny spots will go away soon enough.