Which plant's root is used to treat anxiety and is known as 'kava'?

The plant whose root is used to make kava and traditionally treat anxiety is Piper methysticum.

Kava, also called ʻawa in Hawaiʻi and yaqona in Fiji, is a Pacific plant in the pepper family. Its prepared beverage is made mainly from the peeled root or underground stem, which is ground or pounded, mixed with water, and strained. Kava has long been served in ceremonial and social settings across Polynesia, Micronesia, and Melanesia.

Its relaxing effects come primarily from kavalactones, including kavain and methysticin, which influence several nervous-system targets, especially GABA-related signaling. Research has found possible benefits for some anxiety symptoms, but studies differ in preparation, dose, and quality; kava is not a universal substitute for medical treatment.

Kava is often confused with valerian, passionflower, or skullcap because all are marketed as calming herbs. Safety also matters: some concentrated or poor-quality products have been linked to liver injury, and kava can interact with alcohol or sedative medicines.