PROBLEM TO BE SOLVED: To provide a slime removal tool for drain, which is installed on a drain and the like in a sink of a kitchen or a bathroom, for removing slime or preventing occurrence of slime, in which a slime prevention/removal effect is not affected by an amount and temperature of water flowing into the drain and a position where the tool is installed.SOLUTION: In the invention, allyl isothiocyanate is used as an active ingredient of a slime suppression agent for a drain.SELECTED DRAWING: Figure 7