多粘菌素B（英语：Polymyxin B，又名多黏菌素B）是一种主要用于治疗 革兰氏阴性菌感染药物。它是从一种名为Bacillus polymyxa的细菌中被分离出来的。多粘菌素B是多粘菌素的一种，由两种非常近似的化合物混合而成：多粘菌素B1和多粘菌素B2。除变形杆菌属外，它对几乎所有革兰氏阴性杆菌均有杀菌作用。多粘菌素的作用原理是与细胞膜粘附，改变细胞膜的结构使之通透性变强，细胞因吸收周围环境过多的水分而膨胀死亡。它是带有正电荷的碱性蛋白，像常用于去污的表面活性剂一样。副作用包括神经毒性以及急性肾小管坏死。

Polymyxin B is an antibiotic primarily used for resistant Gram-negative infections. It is derived from the bacterium Bacillus polymyxa. Polymyxin B is composed of a number of related compounds (see "Mixture composition"). It has a bactericidal action against almost all Gram-negative bacilli except the Proteus and Neisseria genera. Polymyxins bind to the cell membrane and alter its structure, making it more permeable. The resulting water uptake leads to cell death. Polymyxins are cationic, basic peptides that act like detergents (surfactants). Side effects include neurotoxicity and acute renal tubular necrosis. Polymyxins are used in the topical first-aid preparation *********.