PROBLEM TO BE SOLVED: To provide a system for supporting prescription preparation with which the quantity of liquid actually used in preparation is accurately and easily obtained, and high-accuracy preparation is performed.SOLUTION: The system for supporting prescription preparation includes: a safety cabinet 1 having a negative pressure work space 10 a metering instrument 30 which is provided in the work space 10 and measures the empty weight of a syringe 2 for extracting liquid from a first container a storage 61 for storing the empty weight an operating instrument 62 for obtaining a suction quantity from a difference between the weight after suction of the syringe 2 sucking a liquid for a predetermined scale from the first container after measuring the empty weight and the empty weight a determination device 63 for determining whether or not the obtained suction quantity is a proper quantity to be injected into a second container in the work space 10 and a display 50 displaying the determination result.COPYRIGHT: (C)2011,JPO&INPIT【課題】実際に調合で用いる液体の量を正確かつ容易に得ることができ、高精度な調剤をおこなえる処方薬調剤支援システムを提供する。【解決手段】陰圧状態の作業空間10を有する安全キャビネット1と、作業空間10内に設けられ、第1容器から液体を抜き取るためのシリンジ2の空重量を測定する計量手段30と、空重量を記憶する記憶手段61と、空重量測定後に第1容器から液体を所定目盛分だけ吸入したシリンジ2の吸入後重量と空重量との差から吸入量を求める演算手段62と、求めた吸入量が、作業空間10内の第2容器に注入すべき適正量か否かを、判定する判別手段63と、判別結果を表示する表示手段50と、を備える。【選択図】図1