* Corresponding author: Sylvanus Beredugo Department of Medical Laboratory Science, Niger Delta University, Wilberforce Island, Amassoma, Bayelsa State, Nigeria. Copyright © 2022 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Histomorphological evaluation of the combined therapeutic potential of Carica papaya and Musa paradisiaca on indomethacin induced gastric injury Sylvanus Beredugo 1, * , Emmanuel U. Eric 1 , Yibala I. Oboma 1 and Onome C. Sadjere 2 1 Department of Medical Laboratory Science, Faculty of Basic Medical Sciences, College of Health Sciences, Niger Delta University, Wilberforce Island, Amassoma, Bayelsa State, Nigeria. 2 Histopathology Laboratory, Nigeria Airforce Medical Centre, Headquarters Mobility Command, Yenagoa, Bayelsa State, Nigeria. World Journal of Advanced Science and Technology, 2022, 02(02), 012–017 Publication history: Received on 18 October 2022; revised on 02 December 2022; accepted on 05 December 2022 Article DOI: https://doi.org/10.53346/wjast.2022.2.2.0049 Abstract Background: Medicinal plants are often used for the preparation of remedies for the treatment of several ailments especially in rural areas. Objective: The study investigated the combined effect of Carica papaya (pawpaw) and Musa paradisiaca (plantain) leaves extract on the stomach walls of albino rats against indomethacin induced gastric ulceration. Materials and Methods: Twenty-five (n-25) albino rats were weighed and divided randomly into five groups. Each group consisted of five (n-5) rats. Group A served as negative control and received rat feeds and water ad libitum. Group B received feeds and a single dose of indomethacin (25 mg/kg body weight) via orogastric administration and organs were harvested 4 hours after administration. Group C rats were administered with Carica papaya leaf extract (250 mg/kg body weight) daily for 14 days. Group D was administered with Musa paradisiaca leaf extract (250 mg/kg body weight) for 14 days. Group E received combined extract of Carica papaya (250 mg/kg body weight) and Musa paradisiaca (250 mg/kg body weight) daily for 14 days. All the animals were allowed access to feed and water. The animals in groups C-E fasted for 24 hours and were administered with a single dose of indomethacin (25 mg/kg body weight). Four hours later, the animals were sacrificed under chloroform inhalation, organs harvested, processed and stained with haematoxylin and eosin for histomorphological evaluation. Result: The result of the study shows that the single dose of indomethacin caused gastric ulceration within 4 hours. Musa paradisiaca leaf extract ameliorated the effect of indomethacin on the stomach. Combination of Carica papaya and Musa paradisiaca leaves extract exacerbated the effect of indomethacin on gastrointestinal tract ulcers. Conclusion: The practice of using combined extract of Carica papaya and Musa paradisiaca should be avoided in ulcer patients or individuals on indomethacin therapy. Keywords: Gastric ulcer; Indomethacin; Carica papaya; Musa paradisiaca 1 Introduction Herbal remedies have been known to be effective in the treatment of various ailments [1, 2, 3, 4]. Musa paradisiaca and Carica papya have been noted for their therapeutic effects in herbal medicine. The extracts of C. papaya contain