Osha (Ligusticum porteri) is a perennial herb that’s part of the carrot and parsley family. It’s often found on the edges of forests in parts of the Rocky Mountains and Mexico (1, 2).

While 12 ligusticum species exist, only Ligusticum porteri is deemed “true” osha (3). 

Osha grows up to 3 feet (1 meter) tall and has small, bright green leaves that look like parsley. It can also be identified by its small white flowers and wrinkled, dark brown roots. 

Also known as bear root, Porter’s licorice-root, Porter’s lovage, and mountain lovage, osha has traditionally been used in Native American, Latin American, and South American cultures for its purported medicinal benefits (3, 4).

The root is considered an immune booster and aid for coughs, pneumonia, colds, bronchitis, and the flu. It’s also used to relieve indigestion, lung diseases, body aches, and sore throats (1).

Today, osha root is most commonly utilized as a tea, tincture, or decongestant.

This article reviews the potential benefits, uses, and side effects of osha root. 

Possible benefits

Osha root is thought to treat respiratory illnesses, sore throats, and lung diseases. However, no studies currently exist to support these claims. 

Still, limited research suggests that osha root and its plant compounds may have health benefits.

May fight oxidative stress and inflammation

Osha root extract may combat oxidative stress due to its potent antioxidant effects (5, 6, 7).

Antioxidants are compounds that fight free radicals, or unstable molecules that cause oxidative stress in your body (8). 

Oxidative stress is associated with chronic inflammation and an increased risk of illnesses, including heart disease, Alzheimer’s, and cancer (9, 10).

One test-tube study found that 400 mcg/mL of osha root extract demonstrated significant antioxidant activity and reduced inflammatory markers (1). 

These effects are thought to be due to Z-ligustilide, one of osha root’s primary plant compounds (6, 7). 

Test-tube and animal studies indicate that Z-ligustilide may safeguard against both acute and chronic inflammation (11, 12, 13). 

While these results are promising, human research is needed.

May protect against infection

Osha root extract and its plant compounds have antimicrobial effects, which may help protect against infection (14, 15).

Traditionally, osha root has been administered topically to disinfect wounds. It has also been used to treat some viral diseases, such as hepatitis. However, no studies currently support the effectiveness of these applications (4, 16). 

Nonetheless, test-tube studies show osha root extract to be particularly effective against numerous bacteria, including Staphylococcus aureus, E. coli, Enterococcus faecalis, and Bacillus cereus (14, 17, 18). 

These bacteria are associated with several illnesses.

Additionally, studies tie the Z-ligustilide in osha root extract to potent antifungal properties (19).

Yet, human research is needed. 

Other potential benefits 

While research is limited to animals, osha root may have other benefits. These include:

  • Reduced blood sugar levels. In a study in mice with type 2 diabetes, osha root extract significantly reduced blood sugar levels after they consumed sugar (20).
  • Protection against stomach ulcers. One study in rats found that osha root extract helped prevent the formation of stomach ulcers (21).

Keep in mind that human studies are needed.

Summary

Overall, very little evidence supports osha root’s supposed medicinal benefits. Still, test-tube and animal studies suggest that it may have antioxidant, anti-inflammatory, and antimicrobial effects.

Side effects and precautions

Due to a lack of human research, osha root’s side effects are largely unknown (22). 

Pregnant or breastfeeding women are strongly discouraged from using any form of osha. 

What’s more, the osha plant can be easily mistaken for poison hemlock (Conium maculatum L.) and water hemlock (Cicuta maculata or Cicuta douglasii), both of which grow alongside osha and are highly poisonous (3, 23, 24).

While all three plants have slight differences in their leaves and stems, the easiest way to identify osha is by its dark brown, wrinkled roots that have a distinct, celery-like odor (3). 

All the same, you may wish to only purchase osha from professionals or certified suppliers rather than harvest it on your own.

Summary

Few safety studies have been conducted on osha, though it’s easily confused with poison and water hemlock. Pregnant and breastfeeding women should avoid it.

Forms and dosage

Osha root is sold in a variety of forms, including teas, tinctures, essential oils, and capsules. The root itself is available whole, either dried or fresh. 

You may also see osha root included in other products, such as herbal teas

However, effective dosages are unknown due to a lack of human research. Therefore, if you’re interested in trying any form of osha root, discuss an appropriate dosage with your healthcare provider. 

Furthermore, be sure that you don’t take more than the recommended serving listed on the product label.

Additionally, the Food and Drug Administration (FDA) doesn’t regulate osha root supplements, so it’s important to buy your product from a reputable source. 

When possible, opt for products that have been certified by a trusted third party testing company, such as US Pharmacopeia, NSF International, or ConsumerLab.

Interestingly, United Plant Savers, an organization whose mission is to protect native medicinal plants, considers this plant an endangered herb. This could affect your ability to find it, and it highlights the importance of purchasing it from reputable companies.

summary

Osha root comes in several forms, including teas, tinctures, and capsules. Yet, due to insufficient research, there’s currently no established recommended dose.

The bottom line

The wrinkled, brown roots of osha, a plant native to the Rocky Mountains and parts of Mexico, have traditionally been used as a decongestant to help treat the flu and common cold. This root is also thought to boost immunity and soothe sore throats.

Although human research to support these uses is lacking, preliminary test-tube and animal studies suggest that osha root may have antioxidant, anti-inflammatory, and antimicrobial effects.

Osha root can be brewed as a tea, crushed into a powder, or consumed as a tincture. It’s best to consult a health professional before adding it to your routine.