Introduction: The anti-inflammatory and immunomodulatory properties of tarragon have been noted. Here, we examined the effects of an aqueous extract of the tarragon plant in a rat model of ulcerative colitis. Methods: Ulcerative colitis was induced in Wistar rats using a 2 ml acetic acid (4%) intrarectal enema. Experimental groups received sulfasalazine (2 mg/kg) or tarragon aqueous extract (100 mg/kg) orally for ten consecutive days. After ten days, the animals were euthanized and evaluated for disease activity index (DAI), production of inflammatory and pro-inflammatory mediators in the intestinal tissue. Results: Both the tarragon aqueous extract and sulfasalazine treatments were effective in reducing the disease severity index in experimental ulcerative colitis. Malondialdehyde intensity, nitric oxide level, and myeloperoxidase activity regressed in the colon of animals treated with the tarragon aqueous extract more than in the group treated with sulfasalazine. However, sulfasalazine significantly reduced TNF-α and IL-1 levels compared to the tarragon aqueous extract. There was no statistical difference in IL-6 and PGE2 reduction between the two groups. Conclusion: These findings suggested that the aqueous extract of tarragon may be applied as a natural resource to control ulcerative colitis.