This study on the effect of ethanolic root extract of Gonglonema latifolium on gastric acid output and ulceration was undertaken due to paucity in scientific reports on the medicinal properties of the root extract especially on gastrointestinal functions. Eighteen (18) albino Wistar rats were randomly assigned into 3 groups of 6 rats each. The control group was fed on normal rat chow + drinking water while the test groups in addition received extract treatment (p.o) at a dose of 100mg/kg and 200mg/kg respectively. The feeding regimens lasted for 14 days. Gastric acid secretion and ulcer studies were done using standard procedures. Results obtained from this study shows that the mean basal gastric acid output (MBGAO) was significantly (P<0.001) higher in the high dose (4.00 ± 0.12mmol/L/hr) and lower in low dose (2.50 ± 0.06mmol/L/hr) extract treated groups compared with control (3.65 ± 0.05mmol/L/hr). The high dose group also showed significant (P<0.05) potentiating effect on histamine induced gastric secretion compared to other groups. The effect of carbachol and atropine on MBGAO was not significantly different among the groups. Mean ulcer scores were also significantly higher in the low dose (P<0.01) and high dose (P<0.001) groups compared with controls. We therefore conclude that ethanolic root extract of Gonglonema latifolium contains phytochemical agents that increase gastric secretion at high doses probably via H2-histaminergic receptors, suppressing gastric acid production at low doses. The extract also has an ulcerogenic effect on gastric mucosa. Hence the use of crude root extract of Gonglonema latifolium should be taken with caution.