What Is Wormwood?

Wormwood (Artemisia absinthium) is a perennial herb that grows back every year. It has been used for medical purposes for thousands of years.

Wormwood's name stems from its historical use as an antiparasitic. The essential oil from this hearty, bitter-tasting herb has also been used to help with digestion, pain management, and to reduce swelling.

This article explains how wormwood is used medicinally, and what's known from medical research about how it works. It also discusses available forms of wormwood and any possible side effects.

What Is Wormwood Used For?

Studies have tested many uses for wormwood. While research is limited, here's what is known.

Crohn's Disease

Crohn’s disease is an inflammatory condition of the digestive system. Symptoms include intense stomach pain, diarrhea, and tiredness. Research suggests there are benefits for people with Crohn's disease who take wormwood, but the results are drawn from small sample sizes.

• In one study, 10 people with the disease were given 750 milligrams (mg) of dried powdered wormwood three times a day for six weeks, in addition to their regular treatment. Ten other people who did not receive wormwood served as a control group. Among those who took wormwood, eight of the 10 reported fewer symptoms while just two in the control group said their symptoms improved. The study also found those who took the supplements had improved mood when compared with the control group.
• A different, older study included 40 adults with Crohn’s disease. They were given either 1,500 mg of wormwood a day or a placebo. Symptoms were greatly improved in 65 percent of those taking wormwood, compared with just 15 percent in the control group. The patients taking wormwood also did not need as many steroids—a common Crohn’s medication—after eight weeks of supplements.

Parasites 

Parasites such as pinworm, roundworm, and tapeworms can infect the intestines and cause digestive health problems. Treatments drawn from compounds in wormwood have been used to treat these infections.

However, most research on wormwood's use as an anti-parasitic is based on animal study results that can't be interpreted as having the same value in humans.

One such study in mice, published in the Journal of Helminthology, found that wormwood caused parasites to lose muscle function and die. The treatment was shown to work as well as some leading anti-parasitic drugs.

Digestion

About two-thirds of Americans experience gastrointestinal symptoms such as gas, bloating, heartburn, stomach pain, constipation, and diarrhea. Research shows that wormwood can help with digestion and reduce spasms in the intestines and stomach.

Wormwood also can boost appetite and help produce saliva, other digestive enzymes, or proteins that help with metabolism and support healthy digestion.

Pain Management

A small study showed that wormwood can improve pain and reduce swelling in the body. The research included 42 people who received either 300 mg of wormwood extract per day, 600 mg of the extract per day, or a placebo for 12 weeks. Participants who took 300 mg per day said their pain levels were better, but the other two groups didn't have the same effect.

A review of research literature published in 2018 found that all Artemisia species like wormwood are helpful herbal medicines for pain. They are thought to have antioxidants that help protect your cells through a chemical reaction. They also may reduce swelling.

Arthritis and Immune Support

Inflammation is linked to many long-term diseases, acute and chronic pain, and reduced immune function. Artemisinin—a compound found in wormwood—may help. It stops the body from making cytokines, a kind of protein that causes inflammation.

Some people use wormwood to relieve the pain and swelling caused by arthritis. One study of 180 people with rheumatoid arthritis (RA) looked at differences between those given either wormwood extract or a placebo for 12 weeks. Those taking the wormwood reported significant joint pain relief, with wormwood found to be safer than some common drugs used to treat RA.

Another study of 90 people with knee pain found that putting 3 percent wormwood ointment on sore joints reduced pain and improved physical function in patients with osteoarthritis. 

Possible Side Effects of Wormwood 

Wormwood is relatively safe for short-term use of two to four weeks by adults, and it has been used longer-term as lesser doses upward of 10 weeks.

Unaltered wormwood contains a chemical compound in it called thujone, which can become toxic, even in small amounts, and these products should be consumed with caution due to the potential for serious side effects. Because of this, wormwood products made in the US are required to have less than 5ppm thujone per dose.

Side effects may include:

• Sleeping issues
• Vomiting
• Nausea
• Dizziness
• Hallucinations
• The need to constantly move
• Seizures

Because wormwood contains ingredients that may cause toxic effects, people with certain medical conditions should not take wormwood.

Contraindications include: 

• Pregnant or breastfeeding: Animal studies show wormwood may cause miscarriage.
• Epilepsy or another seizure disorder: Wormwood contains thujone, which is known to cause seizures. Wormwood may also reduce the effects of some anti-seizure drugs.
• Heart disease: If you are taking Coumadin (warfarin) for heart health, wormwood may cause bleeding.
• Kidney disease: Wormwood is toxic to the kidneys and may lead to kidney failure.
• Allergies: Wormwood is part of the Asteraceae family. If you are allergic to anything in this group, such as ragweed or marigolds, avoid wormwood.

Wormwood Dosage and Preparation 

There are currently no specific dosage guidelines for wormwood. Be sure to follow all recommended dosages on the labels of commercially available wormwood products. Large amounts can cause serious side effects.

Wormwood is usually used as a tea. It also may be used as an extract, in some cases applied to the skin as an essential oil. Dried (not fresh) leaves can be used to make wormwood tea. 

Wormwood tea recipe: 

• Let 1/2 to 1 teaspoon of dried wormwood leaves sit in one cup (250 mL) of boiling water.
• Let it sit for five to 10 minutes; the longer it steeps, the more bitter the flavor. 
• Add peppermint, honey, or lemon juice to taste (not required).

What to Look For

Wormwood is available at health food stores and online. It may be found in essential oil, pill, and liquid extract forms.

The U.S. Food & Drug Administration (FDA) lists wormwood as unsafe for internal use because it contains thujone, which is toxic. The FDA requires all wormwood products sold in the U.S. to be thujone-free.

Be sure to look for a product that contains a seal of approval from a third party organization that provides quality testing. These organizations include U.S. Pharmacopeia, ConsumerLab, and NSF International. A seal of approval confirms that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants.

Summary

Wormwood is proven to have many benefits but be sure to talk to your doctor before taking it. It is also important to think about the possible side effects and decide if the benefit is worth the risk.

A Word From Verywell

Wormwood is a nutrient-dense herb that has proven benefits for people with Crohn’s disease and arthritis. It can also remove unwanted parasites from the body, such as pinworm and malaria, and helps with healthy digestion.

As with any dietary supplement, it is important to speak with your healthcare professional before using wormwood. They may be able to guide you to the right form and dosage of wormwood for you.