药用抗生素主要用于细菌、真菌、原虫等的感染症和癌的化学疗法等方面。作为感染症的治疗药,有些抗生素能抑制病原菌,而对宿主的影响小,显示出很好的选择毒性。然而很多抗癌抗生素,对癌细胞和正常细胞的选择毒性一般较低,引起较强的骨髓抑制等副作用。抗菌性抗生素的选择毒性,大多数是由于微生物和动物之间抗生素的一次作用点或化学受体之不同所引起的。所谓一次作用点指的是在抗生素进入微生物的过程(运送)中,在细胞内最初作用的位点。人们认为,一般药的作用是在分子水平上与生物体内物质结合而引起反应的。然而, Medicinal antibiotics are mainly used in bacteria, fungi, protozoa and other infections and cancer chemotherapy and so on. As a therapeutic medicine for infectious diseases, some antibiotics can inhibit pathogens, but little effect on the host, showing a good choice of toxicity. However, many anti-cancer antibiotics, the selective toxicity of cancer cells and normal cells are generally low, causing strong side effects such as myelosuppression. The selective toxicity of antibacterial antibiotics, mostly due to a point of action of antibiotics between microorganisms and animals, or differences in chemical receptors. The so-called primary point of action refers to the initial role of the site in the process of the antibiotic into the microorganisms (transport). It is believed that the general drug’s role is to react at the molecular level with substances in the organism. however,