The aim of this study was to examine the transport mechanism of colloidal particles from subcutaneous tissue to lymphatics. The mechanism of lymph transport was studied in leg prenodal lymphatics of anesthetized rabbits using Imagent LN (60% W/V perfluorooctyl bromide [PFOB] emulsion). Extracellular (dispersed particles) and intracellular (phagocytosed particles by macrophages) PFOB transport was measured in lymph fluid after 0.1ml injection of fluorescently labeled PFOB emulsion into the dorsal skin of the rabbits' foot. Samples were collected from cannulated lower leg prenodal lymphatics. Particles of PFOB emulsion were observed by using a fluorescent technique. The foot/leg were moved passively in a rotary direction at 0.3Hz. Extracellular and intracellular PFOB could be determined in the lymph samples. These findings indicate that both intracellular and extracellular transport mechanisms play a role in the uptake of colloidal particles from interstitial tissue to lymphatics.