目的　从细菌形态和超微结构探讨壳聚糖抗幽门螺杆菌 (Hp)的作用机理。方法　将Hp与壳聚糖作用 2 4h后 ,在透射和扫描电镜下观察Hp的细菌形态和超微结构变化。结果　 (1)透射电镜结果 :Hp形态多样 ,以球形体为主 ,并可见V形、U形和不规则形 ;Hp菌胞壁变薄不完整 ,有的菌体细胞壁部分或全部脱落消失 ,细菌轮廓模糊 ,结构不清 ,且发生不同程度的凹陷变形 ,甚至穿孔和破碎 ;胞浆内容物稀疏 ,空隙明显扩大 ;细菌内部结构消失或分布异常 ,胞质不均匀或密度下降 ,出现高电子密度颗粒。 (2 )扫描电镜结果 :Hp形态多样 ,以球形体为主 ,并可见U形和不规则形 ;细菌表面广泛改变 ,黏附有可折射物质 ,外观呈毛刺状。结论　壳聚糖可能通过破坏Hp外膜的结构、功能和通透性 ,使细菌内容物渗出 ,细菌破裂 ,并从破损的细胞外膜进入Hp内 ,与胞质作用 ,扰乱其代谢。这二方面机制发挥抗Hp作用 Objective To explore the mechanism of action of chitosan against Helicobacter pylori (Hp) from bacterial morphology and ultrastructure. Methods Hp was treated with chitosan for 24 hours. The morphology and ultrastructure of Hp were observed under transmission and scanning electron microscope. Results (1) Transmission Electron Microscopy (TEM) results: Hp forms are diverse, mainly spherical, V-shaped, U-shaped, and irregular; Vp cells have incomplete cell wall thinning, and some or all cell walls are lost and disappeared. Bacteria have blurred contours, unclear structures, and varying degrees of sag deformation, even perforation and fragmentation; sparse cytoplasm content, significant expansion of voids; disappearance or abnormal distribution of bacterial internal structure, uneven cytoplasm or density, high electrons appear Density particles. (2) Scanning Electron Microscope (SEM) results: Hp forms are diverse, mainly spherical, with U-shaped and irregular shapes; bacterial surface is extensively changed, with refracting substances attached, and the appearance is burr-like. Conclusion Chitosan may destroy the structure, function and permeability of the Hp outer membrane, causing the bacterial contents to seep out, break up the bacteria, and enter the Hp from the damaged outer cell membrane, which interacts with the cytoplasm and disrupts its metabolism. These two mechanisms play an anti-Hp role