Historically, at the Dragon Boat Festival, in addition to eating glutinous rice dumplings and participating in the Dragon Boat race, people also drank realgar wine and hung May wormwood grasses on walls. Realgar is a mild mineral which smells pungent and is toxic. In traditional Chinese medicine, realgar is used as an antidote and pesticide. Drinking realgar wine at the Dragon Boat Festival is commonly believed to help people ward off "the five venomous insects" – the centipede, the scorpion, the house lizard, the spider, and the snake. As the tiger is considered to be able to defeat "the five venomous insects", parents would often inscribe the Chinese character for "tiger king" with realgar wine on the foreheads of their kids, hoping that the kids would be as strong as a tiger.

At the Dragon Boat Festival, it was common for people to hang wormwood grass on their doors to ward off evil spirits. In Guangzhou, the custom of hanging wormwood grass on doors is attributed to the Huang Chao Uprising (875-884 AD). According to historical records, shortly after the outbreak of the uprising, there were rumors that Huang Chao's troops had killed eight million people. The rumors terrified residents in neighboring regions and many people fled their hometowns to avoid slaughter. One day, an elderly man who was running away from his hometown came across Huang Chao. Not realizing that the stranger was Huang Chao, the elderly man said to him: "Huang Chao is coming to town. His troops kill innocent people without batting an eyelid. Run for your life." Hearing this, Huang Chao realized that the elderly man had believed in the rumors about his troops. So he told the elderly man that his troops only killed bad people, but not good people. He then urged the elderly man to go home and hang wormwood grass on his door as a sign to tell the troops that he was a good person. The elderly man did as what he was told and also had all of his fellow villagers hang wormwood grass on their doors. The entire village was thus spared when Huang Chao's troops arrived as Huang had told his soldiers to leave alone households with wormwood grass on their doors. As the day coincided with the Dragon Boat Festival, the practice of hanging wormwood grass on doors eventually evolved into a custom of the Dragon Boat Festival. As a matter of fact, wormwood grass smells slightly pungent and therefore has a repelling effect on insects, whose numbers typically begin to increase around the Dragon Boat Festival.

Historically, at noon of the Dragon Boat Festival, families would also paste on their doors yellow paper bearing variants of Chinese characters written by Taoists. The paper was believed to be able to repel evils.