Antitussive agent comprising a silicon dioxide powder having an oil absorption of 35 mL / 100 g or more. A composition for combating weed beddy weevers containing the above-mentioned Bedbird pest control agent. A method for combating bed soap control, wherein a silicon dioxide powder having an oil absorption amount of 35 mL / 100 g or more is brought into contact with a bedbug.吸油量が35mL/100g以上である二酸化ケイ素粉末からなる、トコジラミ駆除剤。前記トコジラミ駆除剤を含有する、トコジラミ駆除用組成物。吸油量が35mL/100g以上である二酸化ケイ素粉末をトコジラミに接触させる、トコジラミ駆除方法。