Provided is a highly palatable and safe glucosyltransferase inhibitor or anti-dental caries agent. A glucosyltransferase inhibitor or anti-dental caries agent having an epigallocatechin gallate polymer or a salt thereof. Particularly, the above agent containing an epigallocatechin gallate polymer, which is a compound in which chroman rings are bonded at position 6 and/or 8 via a methylene group.本發明係提供偏好性高且安全性高之葡萄糖轉移酶抑制劑或抗齲蝕劑。該葡萄糖轉移酶抑制劑或抗齲蝕劑係具有表沒食子兒茶素沒食子酸酯聚合物或其鹽。且前述製劑係特別含有於色滿環之第6及/或第8位置,介由亞甲基所結合的化合物之表沒食子兒茶素沒食子酸酯聚合物。