Most patients with cholangiocarcinoma (CCA) develop extrahepatic malignant biliary obstructions, which require palliative drainage to normalize bilirubin levels and to improve the patients' overall survival. Here, we report that the infusion of methotrexate-containing plasma-membrane microvesicles derived from apoptotic human tumour cells into the bile-duct lumen of patients with extrahepatic CCA mobilized and activated neutrophils and relieved biliary obstruction in 25% of the patients. Neutrophil recruitment by the microvesicles was associated with an increase in uridine diphosphate glucose and complement C5, and led to the degradation of the stromal barrier of CCA. The microvesicles induced pyroptosis of CCA cells through a gasdermin E-dependent pathway, and their intracellular contents released upon CCA-cell death activated patient-derived macrophages into producing proinflammatory cytokines, which attracted a secondary wave of neutrophils to the tumour site. Our findings suggest a possible treatment for the alleviation of obstructive extrahepatic CCA with few adverse effects, and highlight the potential of tumour-cell-derived microvesicles as drug carriers for antitumour therapies.