Valerian dates back to Hippocrates who prescribed it for sleep around 400 BCE. The name comes from the word valere, meaning to be strong or healthy, and it was believed that it had the ability to turn anything bad into good. Valerian has been used to treat coughs and relax labored breathing, and in World War II was used to treat soldiers experiencing PTSD. Valerian is believed to work by increasing GABA levels in the brain. Over 2000 years later, valerian is still most commonly used for insomnia and other sleep troubles.