There is a special custom during the Dragonboat Festival, and that is drinking Realgar Wine. Realgar is a type of medicine that detoxifies people and kills pests. This is why people in ancient times believed that drinking Realgar Wine kept them healthy.
In the famous Legend of the White Snake, the thousand-year-old snake spirit Bai Su-zhen only drank a few cups of Realgar Wine during the Dragonboat Festival, and lost all her powers. This made her reveal her true form in front of her beloved Hsu-hsian, and scared him to death.
Realgar Wine can make a thousand-year-old snake spirit lose her magical powers, not to mention other poisonous animals. For children who are too young to drink wine, there is another way to keep them safe: Take powdered Realgar and write “王 (king)” on the child’s forehead for the same protective effect.