Acorus calamus is ill. During the Dragon Boat Festival in the south of the Yangtze River, people hang calamus and mugwort leaves on doors and windows and drink calamus wine to ward off evil spirits and prevent epidemic. On summer and autumn nights, the custom of burning calamus and mugwort leaves to repel mosquitoes and insects has been maintained to this day. The flag leaves of Acorus calamus are green, dignified and beautiful, and it is a good indoor potted ornamental plant. The bonsai made of calamus is both poetic and pollution-resistant. The ancients often put a pot of calamus under the oil lamp when reading at night. The reason is that Acorus calamus has the function of adsorbing dust in the air and can avoid the pain of smoking eyes. Acorus calamus is an excellent "green pesticide". Mashing 500 grams of Acorus calamus rhizome, adding 1- 1.5 kg of water and boiling for two hours, and mixing the filtered stock solution with 3-6 kg of water, can effectively control rice planthoppers, rice leafhoppers, stem borers, aphids, red spiders and other pests.