Background: Hypoestes rosea, an evergreen shrub belonging to the Acanthaceae family possess antiulcer potential amongst its several other medicinal properties, including usefulness as anti-diabetic and anti-inflammatory agents. Objective: In this study, we investigated the anti-secretory effect of aqueous leaf extract of H. rosea as the possible mechanism for its antiulcer activity in gastric ulcer induced rats. Methods: 40 rats were divided into 2 experimental phases of 20 rats each. They were further separated into 5 groups as follows: Group 1 (Normal control: rat chow and water only). Group 2 Ulcer control: Indomethacin-induced (40mg/kg bw). Group 3: Low dose (100mg/kg bw). Group 4: Medium dose (200mg/kg bw). Group 5: High dose (300mg/kg bw). Phase 1 involved determination of ulcer lesion index and % inhibition. Phase 2 involved estimation of gastric acid secretion using the method of continuous perfusion with 10minutes aliquots titrated against 0.01N NaOH. Results: Aqueous extract of Hypoestes rosea produced a significant (P<0.05) dose-dependent decrease in ulcer lesion score with an accompanying increase in percentage inhibition at the various doses used in the study (100, 200 and 300 mg/kg bw). Also, there was a significant decrease in basal and histamine-induced acid secretion at all doses with the greatest effect observed at the high dose (300mg/kg bw). Conclusion: Results obtained showed that aqueous extract of H. rosea decreased gastric acid secretion possibly due to inhibition of Histamine receptors and may thus be the mechanism for its anti-ulcer activity.