Background Liposuction has become one of the most frequently performed procedures in the field of aesthetic surgery. Fat embolism syndrome after liposuction can easily be overlooked or underestimated; however, occasionally, fulminating fat embolism syndrome can develop and lead to a critical situation within 2–3 days after lipoplasty. Changes over time in the amount of circulating fat particles and the histology of major organs have not yet been studied. Methods This study was conducted using 18 male Sprague-Dawley rats aged 12 weeks and weighing 500–628 g (average, 562 g). Fifteen rats were used as the experimental group and 3 as the control group. Under general anesthesia, tumescent-technique liposuction was performed at the lateral flank areas and abdomen for 1 hour. Blood, lung, and brain tissue specimens were obtained at 1 hour, 1 day, and 2 days after the liposuction procedure. Results The average number of fat particles in the blood samples was 25,960/dL at 1 hour, 111,100/dL at 24 hours, and 21,780/dL at 48 hours. The differences between study groups were statistically significant. Both intravascular and extravascular fat particles with inflammation were seen in all 15 rats, as were inflammatory cell infiltration, hemorrhage, and consolidation with shrinkage of the lung alveoli. Conclusions These results imply that there is a strong possibility of fat embolism syndrome after liposuction in real clinical practice, and the first 24–48 hours after the operation were found to be the most important period for preventing pulmonary embolism and progression to fulminating fat embolism syndrome.