Further work was undertaken to clarify the mechanism of enhanced delivery of anticancer agents into rat lymph nodes by water-in-oil (W/O) emulsions. Radiolabeled [131I] iodohippuric acid (IH, watersoluble model compound) and [14C]tripalmitin (TP, tracer of oil) were administered intramuscularly, and radioactive concentrations in blood, lymph nodes, and muscles were determined. Also, a new type of emulsion, gelatin-containing W/O (W/O-G) emulsion, was manufactured to be used as a delivery system for the anticancer agents. It was found that the rate of transfer of TP into lymph nodes was enhanced in the following order: oil, oil-in-water (O/W) emulsion, W/O emulsion, and W/O-G emulsion. The transfer of IH into lymph nodes was enhanced more effectively by W/O-G emulsion. The results of this study suggest the existence of a special transport mechanism through which drug and oil are delivered together.