When nanoparticles get into a living body, they interact with body fluids. This study shows high physicochemical persistence of electroexplosive aluminum nanoparticles in physiological solutions simulating body fluids: Artificial Sweat (ASw), Simulated Saliva (SS), Simulated Gastric Fluid (SGF), and Artificial Alveolar Fluid (AAF). It has been demonstrated that after 14 days of exposure in ASw - SS - SGF - AAF solutions, the average size of initial 90 nm nanoparticles became 90 - 100 - 230 - 90 nm, and the average size of initial 5 μm agglomerates became 1.6 - 0.9 - 1.0 - 3.0 μm, respectively. According to s SEM data, the exposed particles retained their spherical shape. With the help of the X-ray phase analysis it was shown that the oxide/hydroxide phase content in nanoparticles did not increase. It has been concluded that highlyreactive aluminum nanoparticles are capable to retain their phase composition, dispersion, and morphology in synthetic body fluids.