Many drugs must be administered intravenously instead of oral administration due to their poor oral bioavailability. The cost of repeated infusion treatment for 6 weeks every year is as high as tens of billions of dollars worldwide. Exosomes are nano-sized (30–150 nm) extracellular vesicles secreted by mammalian cells due to environmental stimulation or self-activation. Milk contains abundant exosomes originated from multiple cellular sources. It has been proved that milk exosomes (MEs) could survive with the strongly acidic conditions in the stomach and degradative conditions in the gut. Furthermore, they can cross biological barriers to reach targeted tissues. The ability of MEs to cross the gastrointestinal barrier makes them as a promising drug delivery tool for oral delivery. This review is devoted to the purification of MEs, their biocompatibility and immunogenicity, and prospects for their use as natural drug carriers for oral administration.

由于口服生物利用度差，许多药物必须静脉内给药而不是口服给药。每年6周重复输液治疗的费用在全球范围内高达数百亿美元。外泌体是哺乳动物细胞因环境刺激或自我激活而分泌的纳米级（30-150 nm）细胞外囊泡。牛奶含有来自多种细胞来源的丰富外泌体。已经证明，牛奶外泌体（MEs）可以在胃中的强酸性条件和肠道中的降解条件下存活。此外，它们可以穿过生物屏障到达目标组织。ME 穿越胃肠道屏障的能力使它们成为一种有前途的口服给药工具。本综述致力于 ME 的纯化，