The tradition of going to the Lhasa River during the bathing Festival has long existed, as people believe that water from that day is as manna and can wash away the filth and doom, and pray for good health, and long life.
In the ancient days of the snowy plateau, the god of medicine came from dispatch to the world. When he just finished his mission and was going to return, at the south bank of Brahmaputra, a terrifying plague spread rapidly, and people suffered. The medicine god saw this situation, and immediately asked the gods for additional help for mankind. He turns into a star and the water illuminated by the star turns into a potion. The plague was eradicated after the people bathed. Because the star only appears for seven days, from July 6 to July 12 in the lunar calendar, Tibetans make this week a bathing festival.
Till now, the people still can see the appearance of a bright star in southeast sky during bathing festival.