Trauma, postpartum haemorrhaging, and coagulation disorders can contribute to major and life-threatening external bleeding. During episodes of severe bleeding, it is often necessary to initiate blood coagulation deep within wounds near the site of damaged vasculature. Current hemostatic agents are often not effective in these situations. To address this challenge, the Kastrup Lab is developing micro and nanoparticles that are waterreactive and can propel upstream through blood, with the goal of externally delivering pro-coagulants that can effectively halt severe haemorrhaging. This project is supported by a $100 000 Stars in Global Health Grant from Grand Challenges Canada.