Ulcerative colitis is an inflammatory disease, and antioxidants with anti-inflammatory effects of silver nanoparticles have been explored. This study investigates the therapeutic potential of silver nanoparticles bio-fabricated using aqueous extract of Citrus sinensis peel (CsPEx-AgNPs) on ulcerative colitis in male Wistar rats. Thirty adult male Wistar rats were assigned into; Non-Colitis Control, Colitis control, Colitis+CsPEx (Citrus sinensis Peel Extract, 250µg/Kg), Colitis+AgNO3 (250µg/kg), Colitis+CsPEx-AgNPs (25µg/Kg) and Colitis+CsPEx-AgNPs (250µg/Kg) groups. Colitis was induced with a single intra-rectal administration of 6% acetic acid (1mL/100g B.W.), followed by oral administration of regimens in groups 3-6 for seven days. Eighth-day post-colitis induction, rats were sacrificed; blood and colon were collected for haematological, biochemical, and histopathological examination. Data were analyzed using one-way ANOVA followed by Tukey’s post-hoc test for multiple comparisons. The colitis control group showed: reduced body weight, increased colonic weight and thickness, diarrhoea and macroscopic scores, a significant decrease in packed cell volume, a significant increase in Platelet count, plateletcrit, red cell distribution width, depleted superoxide dismutase, glutathione, catalase levels and elevated concentrations of malondialdehyde, myeloperoxidase and tumour necrosis factor-α, mucosal ulceration, infiltration of inflammatory cells in the mucosa and submucosa. Treatment with CsPEx-AgNPs increased body weight, reduced colonic weight and thickness, diarrhoea, and macroscopic scores; improved red blood cell and platelet indices; enhanced superoxide dismutase, glutathione, catalase levels and reduced the concentrations of malondialdehyde, myeloperoxidase and tumour necrosis factor-α; reduced cellular infiltrates and restored mucosal epithelial layer. CsPEx-AgNPs have an anti-colitic effect and may provide therapeutic potential for the treatment of ulcerative colitis.