Haloperidol for use in a method of treating transverse colon cancer, said method comprising (a) before operation: administering haloperidol orally at a daily dose of 0.375 mg in a tablet form before bedtime, administering 6.0 g of CPG, which contains 1200 mg of ascorbic acid and 18 mg of calcium pantothenate, on an empty stomach, at hospitalization, infusing 500 ml of an Aldofed injection solution which contains maltose, potassium chloride, magnesium chloride, potassium hydrogen phosphate, potassium dihydrogen phosphate, sodium chloride, magnesium chloride hexahydrate, anhydrous sodium acetate, maltose monohydrate at decreased appetite, administering two tablets of 25 mg Luvox which contains fluvoxamine maleate orally at reduction in blood potassium, and administering 1 to 2 tablets of Ferromia which contains sodium ferrous citrate orally on an empty stomach at anemia; (b) removing the tumor as much as possible; and (c) beginning at 5 days after operation and lasting for at least 3 month after operation: administering haloperidol orally at a daily dose of 0.375 mg in a tablet form before bedtime, administering 6.0 g of CPG, which contains 1200 mg of ascorbic acid and 18 mg of calcium pantothenate, on an empty stomach, administering two tablets of 25 mg Luvox which contains fluvoxamine maleate orally at reduction in blood potassium. (a) before operation: administering haloperidol orally at a daily dose of 0.375 mg in a tablet form before bedtime, administering 6.0 g of CPG, which contains 1200 mg of ascorbic acid and 18 mg of calcium pantothenate, on an empty stomach, at hospitalization, infusing 500 ml of an Aldofed injection solution which contains maltose, potassium chloride, magnesium chloride, potassium hydrogen phosphate, potassium dihydrogen phosphate, sodium chloride, magnesium chloride hexahydrate, anhydrous sodium acetate, maltose monohydrate at decreased appetite, administering two tablets of 25 mg Luvox which contains fluvoxamine maleate orally at reduction in blood potassium, and administering 1 to 2 tablets of Ferromia which contains sodium ferrous citrate orally on an empty stomach at anemia; administering haloperidol orally at a daily dose of 0.375 mg in a tablet form before bedtime, administering 6.0 g of CPG, which contains 1200 mg of ascorbic acid and 18 mg of calcium pantothenate, on an empty stomach, at hospitalization, infusing 500 ml of an Aldofed injection solution which contains maltose, potassium chloride, magnesium chloride, potassium hydrogen phosphate, potassium dihydrogen phosphate, sodium chloride, magnesium chloride hexahydrate, anhydrous sodium acetate, maltose monohydrate at decreased appetite, administering two tablets of 25 mg Luvox which contains fluvoxamine maleate orally at reduction in blood potassium, and administering 1 to 2 tablets of Ferromia which contains sodium ferrous citrate orally on an empty stomach at anemia; (b) removing the tumor as much as possible; and (c) beginning at 5 days after operation and lasting for at least 3 month after operation: administering haloperidol orally at a daily dose of 0.375 mg in a tablet form before bedtime, administering 6.0 g of CPG, which contains 1200 mg of ascorbic acid and 18 mg of calcium pantothenate, on an empty stomach, administering two tablets of 25 mg Luvox which contains fluvoxamine maleate orally at reduction in blood potassium. administering haloperidol orally at a daily dose of 0.375 mg in a tablet form before bedtime, administering 6.0 g of CPG, which contains 1200 mg of ascorbic acid and 18 mg of calcium pantothenate, on an empty stomach, administering two tablets of 25 mg Luvox which contains fluvoxamine maleate orally at reduction in blood potassium.