In certain locality, the Osha root is also known as bear root. This root is collected from Ligusticum porteri species of plant. Native Americans used this herb to treat multiple disease conditions associated with cardiac and lung-related health issues. Osha plants are preferably growing in high elevated areas.  In the traditional medicinal system, this species of plant is used for boosting immune functioning. Traditionally Osha root is boiled with water to prepare the herbal tea and given to patients suffering from gastrointestinal problems, headaches, and fevers. 
Hispanics from New Mexico and Southwestern United States people are traditionally using this herb from long back. It was thought that the name of this plant (Osha) was given by Hispanic communities, as most of the places belong to New Mexico is started with the name of Osha. 
Hispanic communities and North Americans are widely used Osha root as a traditional medicinal system ingredient to treat respiratory problems like bronchitis, influenza and related conditions. The paste or liniments prepared with Osha root are applied as dressing material to accelerates wound healing. Osha root tea, tincture, and ointment are used for relieving headaches, sinuses. These benefits can be obtained by chewing raw Osha root pieces. 
Following are different traditional uses of this herb in different cultures:
The phytochemical composition of Osha root consists of butylidenephthalide, ligustilide, and Z-ligustilide. 
The detail phytochemical analysis reported that perlolyrine, tetramethylpyrazine are two alkaloids present in this herb, anthraquinone like chrysophanol, phenolic compounds like caffeic acid, ferulic acid, phenylpropanoids, coumarins, furanocoumarins, phthalides like ligustilide, butylidenephthalide, senkyunolide, and 4-hydroxy-3-butylphthalide are present in this Osha root. α-pinene, β-pinene, and limonene are the terpenoids present in Osha root. 
The phytochemicals present in Osha root are responsible for its many medicinal health benefits. For example:
Researchers have found that Osha root has cytotoxic effect with potent antioxidant properties with immunomodulatory effects. These properties are effective against cancer growth. Research studies reported that the Osha root preparation with the dose of 50–400 μg/mL effective against human promyelocytic leukemia cells by reducing oxidative stress and inflammatory suppression ability.
This research also concluded that Osha root preparation reduces lipid peroxidation and prevents the damage of oxidative stress-induced DNA modulation and cancer progression. Osha root preparation also suppressed interleukins production and release. 
There are different dosage forms of Osha Root are formulated by the herbal medicinal companies. Following are some commonly available dosage forms:
Osha root tincture: This is an effective dosage form recommended for cold, flu, sore throat, cough, pneumonia, bronchitis, sinus, H1N1 influenza, and other bacterial or viral respiratory infections. It is also recommended for Viral infections including herpes, HIV, etc. This preparation also improves digestion ability.
Osha root powder, tea, encapsulation are the other forms of Osha root formulations available in herbal dosage forms. Some preparations are used for inhalation purposes also for chest congestion, sinus blockage, etc. The patient needs to thoroughly read the instructions given in the package insert for an effective result. [5,6] The recommended dosage of liquid preparation varies from symptom to symptom. In bronchial dilation condition, 1/4 to1/2 teaspoon of Osha root tincture is prescribed for 5 days with a small amount of water or other juice to mask the taste. At the initial phase, the dose recommendation is lower and gradually increase depending upon the patient’s response and to avoid side effects reactions. The herbalist may suggest intaking 1/4 teaspoon of Osha root preparations just before or after a meal to improve digestion. The usually recommended dose for infection treatment is 20 to 60 drops for 5 days. Mixing with honey for respiratory infection is a better option to make the Osha root liquid preparation palatable.
The following are some of the specific uses of Osha root herbal preparations.
Both antibacterial and antiviral properties of Osha root are effective to treat a wide range of respiratory infections. The anti-inflammatory property of the Osha root is effective to alleviate the inflammatory condition of the mucous membrane of the respiratory tract and bronchial passage opens up. These mechanisms help in easy breathing.
Osha root also helps in digestion, especially during indigestion conditions. 
Osha root increases blood circulation and some individuals are allergic to these herbal preparations. Osha root preparation may cause kidney and liver problems with prolonging therapy. It is also advised not to take with other medications to avoid drug-herb interactions.
When should I avoid Osha root?
Osha root is not recommended during lactation. It is not advised to intake during pregnancy, as it can cause miscarriage. It is strictly restricted to use with other bronchial dilators.