The aim of the investigation was to visualize transport of antibodies produced in the small intestine of the preliminarily sensibilized rats. Horseradish peroxidase (HP) was used as an antigen. Visualization of antibodies was performed by means of determining HP activity (R.S. Graham and M.G. Karnovsky method, 1966). In the lamina propria of the tunica mucosa of the sensibilized rat small intestine, plasmocytes synthesizing antibodies appeared on the 4th day after a challenge dose of the antigen had been injected. The synthesized immunoglobulins were transported in two directions: via epithelium in the intestinal lumen and into the vessels of the lamina propria of the small intestine tunica mucosa. These both processes occur by means of micropinocytosis. Out of the intestinal vessels the antibodies get into the system of the hepatic portal vein and are detected in the sinusoid capillaries and further they get into the perisinusoid space (Disse). Besides, the reaction product is revealed in micropinocytic vesicles situating in cytoplasm of hepatocytes and in bile capillaries. Thus, antibodies synthesized in the lamina propria of the small intestine tunica mucosa get into the intestinal lumen not only through epithelium, but also through biliary system of the liver.