Indigowoad Root / Ban Lan Gen used in China for over 2000 years. It’s cooling, clearing the heat and toxins, used for cold or flu with heat signs like fever, sore throat, swollen glands.
There’s a folk legend of Indigowoad Root / Ban Lan Gen
The Dragon King of the East China Sea and the Dragon King of the South China Sea were shocked and suspicious when they saw the corpses of human beings on the way back from the Heaven Palace to the Dragon Palace. After inquiring, it turned out to be caused by the epidemic in the human world. If not controlled, it will spread into the sea. The two dragon kings were anxious and quickly discussed the countermeasures. Bluegreen Golden Dragon from South China Sea who has a generous heart, took the initiative to ask for his life, vowing that if not, to get rid of the plague and never return to the Dragon Palace. The Dragon King was very happy and sent him to work together with the East Sea Dragon to eliminate the plague. The East Sea Dragon King’s grandson Purple Silver Dragon heard the news and jumped up to the Dragon King. He insisted to let him go to the world with Uncle. The East See Dragon was worried that he wouldn't be able to find enough Dragons to go to the world, because his Dragons were busy building an underwater paradise, he agreed. Bluegreen Golden Dragon and Purple Silver Dragon bid farewell to the dragon king, pretending to be medical doctors, and came to the world. The uncle and nephew first went to the medicine king Buddha to take the medicine seeds and spread them all over the place, and taught people carefully taking care of the medicine plant.
Soon, the medicinal seedlings developed vigorously and grew lush like reeds by the lake. The two uncles and nephews taught people to cook the root of this medicine for the patients. This kind of magic medicine actually has a miraculous effect, and patients recover quickly one by one. Therefore, regardless of the age of men, women and children, the Bluegreen Gold Dragon and the Purple Silver Dragon were treated as gods and guests. The uncle and nephew were deeply moved and decided to stay in the world forever to concentrate on preventing the plague. It's August 15th, the day they should go back to the Dragon Palace. In the evening, the uncles and nephews came to the beach, kneeled on their knees, and thanked Dragon King for their kindness. Then, they hand in hand went into the medicine plant field and turned into two particularly strong medicine seedlings. People know that this medicine seedling was changed by the nephew and his uncle. People called this medicine root "Dragon Root".
In later times, medical doctors renamed it "Ban Lan Gen".