What Is Osha Root?

Osha capsules, tincture, liquid, dried herb

Verywell / Anastasia Tretiak

Osha root (Ligusticum porteri) is a perennial herb in the carrot and parsley family (Apiaceae/Umbelliferae). In North America, there are 12 species of Ligusticum. Among these, L. porteri is known as "true" osha.

Osha is common along forest edges and ravines of the Rocky Mountain Colorado Columbine and Aspen Bluehills. The plant can grow up to 3 feet tall.

In traditional Native American and Hispanic medicine, osha is used as a treatment for a number of upper respiratory conditions. Today, the extract is commonly used as a decongestant. Some believe it also boosts the immune system.

This article discusses the herbal supplement osha, its purported uses, and what you should know before you take it.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF. However, even if supplements are third-party tested, that doesn’t mean that they are necessarily safe for all or effective in general. It is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredients: Z-ligustilide, Z-butylidenephtalide, Diligustilide
  • Alternate names: Bear root, chuchupate, Colorado cough root, Indian parsley, Perejil de Campo, Racine d'Ours, wild celery root, mountain lovage
  • Legal status: Legal in the US and sold over the counter
  • Suggested dose: No standard dose for osha exists
  • Safety considerations: Do not take while pregnant or breastfeeding. Osha looks similar to a toxic plant called poison hemlock, so you should not harvest it yourself.

Uses of Osha

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease.

North American indigenous groups traditionally used osha as a ceremonial drug, incense, food, and medicine. Some of the medical conditions these groups treated with osha include:

In Mexico, the Tarahumara believed L. porteri could protect people from witches and rattlesnakes. It was also used to connect with the spirit world, and the roots were sometimes burned during ceremonies.

Today, some people believe osha root can help treat medical conditions including:

These health claims have not been proven in studies.

Proponents and supplement manufacturers also claim osha root extract can help people with asthma, emphysema, and other respiratory infections.

The FDA has warned multiple osha suppliers and distributors about making medical claims, since this would qualify osha as a "unapproved drug."

If you are considering using osha, you should talk to your healthcare provider or a trained herbalist or naturopathic doctor to understand whether it would be safe for you.

Researchers are examining the composition of osha and how it might provide health benefits. To date, there is no research proving that osha can heal specific health conditions.

Oxidative Stress

Some studies have looked at the root’s protective effect on oxidative stress. Oxidative stress is caused by an imbalance of free radicals and antioxidants and can result in illness and disease.

In a 2016 study, researchers extracted human peripheral lymphocytes (a form of a white blood cell). The cells were incubated with different concentrations of osha root extract. They measured the protective effect of osha against oxidative damage by inducing oxidative stress.

At the highest doses (400 micrograms per milliliter), the researchers found that osha might provide protective effects against oxidative damage.

The following year, the researchers tested osha root extract on human promyelocytic leukemia cells. The goal was to see osha's effects on oxidative stress and inflammation.

Researchers incubated the leukemia cells with different concentrations of osha root. They found that the extract didn't reduce or treat the leukemia cells. It did, however, have a protective effect against oxidative stress and inflammation.

These studies did not include human trials. Human trials are needed to determine dosages and safety of ingestion, among other things.

Oxidative stress can play a role in certain diseases, such as cancer and diabetes. Still, more studies are needed to determine whether osha root would be beneficial for any of these conditions.


Osha root is sometimes used to prevent infections. This is because it’s thought to have antibacterial and antiviral properties. It has been applied directly to wounds to prevent infections and help with healing.

While some studies have found that extracts of osha root can inhibit bacteria, more research is needed to prove its effectiveness for this use.

Osha root has also been used in the treatment of viral infections, including HIV/AIDS. This is because of its suspected antiviral properties. However, there is limited evidence to support this use.

What Are the Side Effects of Osha?

The side effects of osha root are largely unknown. It appears to be well tolerated when taken in small doses over short periods of time.


It's unsafe to consume osha when you're pregnant or breastfeeding. Ingesting osha may trigger menstruation in pregnant women, which could cause miscarriage.

Effects during breastfeeding are unknown, so it's recommended that you avoid osha completely.

Osha must be prepared carefully. The root can be confused with the poisonous plant hemlock, which is fatal if ingested.

Osha and hemlock can often be differentiated by examining their roots.

  • In most cases, poison hemlock roots are smooth and purplish without leaf base remnants, though those features are inconsistent.
  • Roots from water hemlock are thought to be purplish, fibrous, and have a soft texture and parsnip scent.
  • Ligusticums, including osha, have root crowns with basal leaves and have a celery-like odor.

Because osha can be difficult to determine from poison and water hemlock, it is safer to buy from a reputable seller rather than to pick or gather it on your own.

Osha dried herb
Verywell / Anastasia Tretiak

Dosage: How Much Osha Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs. 

There's no scientific data to establish target ranges for specific uses of osha root. This makes it hard to determine an appropriate dose.

Several factors, such as age and health, should be taken into consideration when determining doses.

Some manufacturers and distributors recommend doses based on its purpose. For example, they may suggest a different amount of osha for an infection versus a digestive issue.

What Happens If I Take Too Much Osha?

Taken in large doses over an extended period of time, osha may lead to kidney or liver toxicity. Some manufacturers’ labels say you shouldn’t use osha if you have impaired or inflamed kidneys.


If you are taking prescription or over-the-counter medication, check with your healthcare provider before taking osha root.

How to Store Osha

Keep osha root and osha root extract in a cool, dry place in its original packaging.

Sources of Osha & What to Look For

Osha is sold in a variety of forms, including:

  • Whole roots
  • Dried root
  • Fresh root
  • Root tincture, a liquid herbal extract
  • Capsules containing root powder

Additionally, it can be found in multi-ingredient products such as tea and syrup.

Since this herbal supplement (like all others) is not regulated by the FDA, it's important to purchase it from a reputable source. If possible, the supplement should be certified by a trusted third party, such as:

  • U.S. Pharmacopeia
  • NSF International
  • ConsumerLab

These types of organizations help ensure supplement safety through independent testing and evaluation. They also make sure supplements don't contain unacceptable levels of contaminants.

Make sure that the label does not make false claims. For example, labels should not claim that osha can treat, alleviate symptoms, or cure a disease. Remember that no such claims have been validated by the FDA.

Any claims should be followed by a disclaimer noting the supplement's inability to cure, treat, or alleviate symptoms. It should also mention the importance of checking with a healthcare provider before use.

Check Ingredient Lists

One major problem with commercial osha is misidentification of species. Some suppliers, manufactures, and herbalists don't differentiate between species of Ligusticum and call it all osha. L. porteri is known as "true" osha and should be the primary ingredient in your supplement.


Osha is an herbal supplement with a history of use in Indigenous American medicine. It is sometimes used to treat common ailments like cough, sore throat, and indigestion. Its medical uses have not been proven through scientific studies, however.

Some studies have suggested that osha root may help prevent infection and protect against oxidative stress, but more research is needed to confirm this.

Osha may be confused with poisonous hemlock plants, so it is best to buy this supplement from a reputable supplier. Always check with your healthcare provider before taking any new supplement.

A Word From Verywell

Researchers have found that osha root extract may have some antiviral and anti-inflammatory properties. Even so, human studies are needed to test the safety of dosing as well as the effectiveness of such claims. Be sure to discuss osha use with your healthcare provider.

As you weigh the decision, you may also want to consider that the popularity of osha has led to over-harvesting of the wild plant. As a result, conservationists have designated it as endangered.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Park Service. Southern Ligusticum.

  2. Quiñonez-Bastidas GN, Navarrete A. Mexican plants and derivates compounds as alternative for inflammatory and neuropathic pain treatment—a review. Plants. 2021;10(5):865. doi:10.3390/plants10050865

  3. Turi CE, Murch SJ. Targeted and untargeted phytochemistry of Ligusticum canbyi: indoleamines, phthalides, antioxidant potential, and use of metabolomics as a hypothesis-generating technique for compound discovery. Planta Medica. 2013;79(14):1370-9. doi:10.1055/s-0033-1350618

  4. Nguyen K, Sparks J, Omoruyi F. Investigation of the cytotoxicity, antioxidative and immune-modulatory effects of Ligusticum porteri (osha) root extract on human peripheral blood lymphocytesJ Integr Med. 2016;14(6):465-472. doi:10.1016/s2095-4964(16)60280-7

  5. Nguyen K, Sparks J, Omoruyi F. Effects of (osha) root extract on human promyelocytic leukemia cells. Pharmacognosy Res. 2017;9(2):156-160. doi:10.4103/0974-8490.204641

By Barbie Cervoni MS, RD, CDCES, CDN
Barbie Cervoni MS, RD, CDCES, CDN, is a registered dietitian and certified diabetes care and education specialist.