Introduction Subcutaneous reserpine has been used for chemical sympathectomy. Its effect to deplete catecholamines in rats has been particularly characterized. Here we report some effects of subcutaneous reserpine that have not previously been described, namely to induce dehydration in rats, and to increase in vivo nitric oxide production in septic rats. Methods Male Wistar rats (~300g) received three subcutaneous injections of reserpine (4.5 mg/kg body weight dissolved in dimethyl sulfoxide) 48h and 24h prior to and during cannulations of carotid artery and jugular vein under inhalational anesthesia with 2% isoflurane. Fecal peritonitis was induced 24h after instrumentation, and Fluid resuscitation (1:1 solution of 6% hydroxyethyl starch 130/0.4 and 5% glucose) was given 2h later at 10 ml/kg/h via the jugular venous catheter. The body weight, blood pressure, and arterial base excess, plasma lactate and nitrate/nitrite levels at 6h post-peritonitis were compared with non-reserpinized rats. Results A total of 22 rats (mean weight, 306 ± 5 g) were pre-treated with reserpine. Of these animals, eight were used as sham-operated controls, and 14 had peritonitis induced. Prior to induction of sepsis, these animals showed marked weight loss (56 ± 2 g; equivalent to 18.3% body weight loss) within 48h. Sham rats presented with metabolic alkalosis and an elevated plasma lactate level, whereas septic rats presented with a more severe metabolic acidosis and higher in vivo nitric oxide production (Table 1). All rats presented with a lower blood pressure at the time of faecal slurry injection. At the 6h timepoint, sham rats responded to fluid resuscitation and their blood pressure was elevated, whereas septic rats remained hypotensive (Table 1). Reserpinized septic rats had a higher 6h mortality rate (28.6% vs. 6.1%, p <0.01), whereas none of the sham died at this timepoint. Conclusion Subcutaneous reserpine induced dehydration in rats within 48h, which resulted in fluid-responsive hypotension and hyperlactatemia. Septic reserpinized rats also developed increased nitric oxide production. Subcutaneous reserpine may as the means of chemical sympathectomy may generate confound results.