['Oxidative stress has been implicated in the pathogenesis of various neonatal diseases involving the intestine. Hydrogen sulfide (H', 'C57BL/6 mice received either intraperitoneal phosphate buffered saline (PBS; n=10) or NaHS (1mg/kg/day; n=10), followed by MS for 3h daily between postnatal day P5 and P9. Control neonatal mice were untreated and were not exposed to MS (n=10). Proximal colon was harvested and analyzed for crypt length, goblet cell number per crypt, oxidative stress and inflammation. Groups were compared using one-way ANOVA with Bonferroni post-test.', 'Compared to controls, MS+PBS mice had shorter crypt lengths, fewer goblet cells per crypt, reduced glutathione peroxidase activity, increased expression of thiobarbituric acid reactive substances and inducible nitric oxide synthase mRNA, as well as increased IL-6, TNFα and myeloperoxidase. Administration of NaHS significantly counteracted these negative effects of MS.'] Is intestinal epithelial injury induced by maternal separation protected by hydrogen sulfide?