As the wan-yiehs are regarded by some as gods of pestilence, a custom arose, particularly in Fukien province, of sending out a boatload of wan-yiehs to drive off evil spirits.
由於王爺有瘟神的說法，因此祭拜儀式中有了「請王爺」的逐疫大典。這種大典通常是在發生瘟疫的地方舉行。古時民間認為瘟疫的流行，是王爺在作祟，便請來道士建醮，大家熱鬧一番，迎神驅鬼，避邪禳災。