XMO-10, a perfluorocarbon surfactant produced emulsions of a perfluorocarbon (Perfluorotripropylamine, FTPA) in vitro which were stable at a range of temperatures for at least 5 days. Most of the emulsion particles were smaller than 1 micron, and all emulsion particles were of these dimensions when the emulsification mixture included 2% lecithin. XMO-10 produced more stable emulsions with smaller particles than did PF68, a widely-used emulsifying agent. XMO-10 was toxic to cells in culture but this toxicity was reduced or abolished when the XMO-10 was emulsified with perfluorocarbon. XMO-10 and lecithin produced relatively stable emulsions of perflurodecalin. Such emulsions, if non-toxic in vivo, might permit excretion of perfluorocarbon through the lungs and thus would permit infusion of sufficient quantities of the preparations to function in oxygen transport in severely anemic animals and man.