A native of the higher altitudes of the Rocky Mountains in the USA, the root of the osha plant is a traditional Native American treatment for indigestion and upper respiratory infections. The related Ligusticum wallichii has been used for nearly 2,000 years in traditional Chinese medicine, and most of the scientific studies of osha were actually performed on the Asian species. Ancient Chinese physicians used plants like osha to ''open the interstices'' or sweat out a respiratory infection. Like its Chinese cousin ligusticum, osha will induce sweating, thought to prevent the development of a full-blown cold or flu. Osha is also used to help coughs become productive. Like other bitter herbs, osha stimulates appetite (''feeds a cold'').