This was an experimental study in which both qualitative and quantitative data was obtained on the effect of different doses of the ethanolic crude extract of Psidium guajava fruit on the number of wet faeces in castor oil induced diarrhea in Wistar albino rats. Acute toxicity was also evaluated in laboratory mice by determination of LD50 and the phytochemical composition of the extract from the plant was determined. All these activities took place in July of 2012.