Abstract
Background: Diarrhea is one of the common health conditions affecting people in less developed countries. The World Health Organization (WHO) has estimated that 1.5 billion episodes of diarrhea occur every year in developing countries, resulting in 3 million deaths.

Aims & Objective: This study was done to evaluate anti-diarrheal potency of the ethanolic fruit extract of Psidium guajava using Wistar albino rats to scientifically validate its continued use by the local people. I was also aimed at determining the acute toxicity in mice and phytochemical composition of the extract.

Materials and Methods: The fruits were collected in July, 2012 from the College of Veterinary Medicine farm, Makerere University, dried for 1 week, ground and macerated in 70% ethanol. The dry extract was reconstituted using normal saline and orally administered to different groups of rats at doses of 200, 400 and 600 mg/Kg. Anti-diarrheal activity was determined using the percentage reduction in the frequency of defecation in rats with castor oil-induced diarrhea. Loperamide (1 mg/Kg) was used as positive control. Phytochemical composition was qualitatively determined as described by Harborne (1998). Acute toxicity was evaluated by determination of LD50 and observations of toxic signs.

Results: The ethanolic crude fruit extract of Psidium guajava showed significant (p<0.05, Dunnet test) antidiarrhea activity evidenced by the reduction in rate of defecation by up to 78.33% at 600mg/kg body weight comparable to loperamide (100%). This activity could be attributed to the phytochemicals such as flavonoids and tannins in Psidium guajava that were present in high levels and have been reported to exhibit antidiarrheal activity through denaturing protein hence forming protein tannates which minimize the intestinal mucosa permeability. The LD50 of the crude ethanolic fruit extract was 10,715 mg/Kg.

Conclusion: The findings of this study show that the fruit of Psidium guajava have a very significant antidiarrhea activity and are safe to use as indicated by the high LD50 value. This supports the traditional use of the ethanolic fruit extract of Psidium guajava as herbal remedy for treatment of diarrhea.

Key words: Psidium Guajava; Fruit Extract; Phytochemicals; Antidiarrheal Activity