It is well documented that the immune and sympathetic nervous system communicate directly through specific nerve connection. The stomach have noradrenergic sympathetic innervation too. This study was performed in order to investigate the effects of immunization on content of norepinephrine (NE) in the stomach of rats. The male Wistar rats (250-300 g) were immunized subcutaneously with 0.1 ml bovine serum albumin in complete Freund's adjuvant (BSA-KFA group). The sham-control animals were treated in the identical manner with saline (Sh group).The norepinephrine content in the stomach of all experimental groups was assayed by reversed phase high-performance liquid chromatography with electrochemical detection (HPLC). Level of anti-BSA antibodies and the NE content of stomach were determined on the 5th, 10th and 20th days after immunization. Anti-BSA antibody production was higher on day 10 than 5, and the highest antibody production was observed on day 20. The NE content of the stomach marked increased on day 5 and 10 in comparison with both controls (intact and sham animals). By day 20, NE content had returned to normal. Our results indicate that initial marked increase of NE content in stomach was consequence of sympathetic activation by antigens stimulation and return of NE content on normal was result of reinstated homeostasis.