以抗癌药物为例，我们考察了剩余药物重复利用的可能性。由于担心细菌污染，残留药物的使用并不普遍。我们将抗癌药物与细菌混合，并研究它们对细菌生长的影响。将抗癌药物卡铂、紫杉醇、依托泊苷、伊立替康、甲氨蝶呤和5-氟尿嘧啶（5-FU）与金黄色葡萄球菌、粪肠球菌、粘质沙雷氏菌和大肠杆菌混合。经过一定时间后，对细菌数量进行计数。伊立替康没有表现出抗菌活性，而 5-FU 对测试的细菌表现出高抗菌活性。 5-FU 还显示出 8-80 μg/mL 范围内的最低抑制浓度值，具体取决于细菌种类。 5-FU 在超过 0.8 µg/mL 时会剂量依赖性地抑制金黄色葡萄球菌生长。据报道，蛋白质合成系统是抗生素的靶标，因此我们使用无细胞蛋白质合成系统来确认抗癌剂抗菌活性的机制。 5-FU和甲氨蝶呤对蛋白质合成有直接抑制作用。建议即使残留药物被细菌污染，也不会出现微生物生长或微生物被药物杀死。通过仔细监测，5-FU 有可能用于抗菌目的。

Using anticancer drugs as an example, we examined the possibility of reusing residual drugs. The use of residual drugs is not widespread because of concerns regarding bacterial contamination. We mixed anticancer drugs with bacteria and investigated their effects on bacterial growth. The anticancer drugs carboplatin, paclitaxel, etoposide, irinotecan, methotrexate, and 5-fluorouracil (5-FU) were mixed with Staphylococcus aureus, Enterococcus faecalis, Serratia marcescens, and Escherichia coli. After a certain period, the number of bacteria was counted. Irinotecan showed no antibacterial activity, whereas 5-FU showed high antibacterial activity against the bacteria tested. The 5-FU also showed a minimum inhibitory concentration value in the range of 8-80 μg/mL, depending on the bacterial species. The 5-FU dose-dependently inhibited S. aureus growth at more than 0.8 µg/mL. Since protein synthesis systems are reportedly antibiotic targets, we used a cell-free protein synthesis system to confirm the mechanism of the anticancer agent's antibacterial activity. The 5-FU and methotrexate had direct inhibitory effects on protein synthesis. It is suggested that even if the residual drugs are contaminated with bacteria, there will be no microbial growth or microbes will be killed by the drug. With careful monitoring, the 5-FU could potentially be used for antimicrobial purposes.