The primary objective of this study was to investigate the pharmacological potential of the ethanolic extract of Zizyphus mauritiana bark. Antioxidant, analgesic, cytotoxic and antidiarrheal activities of the extract were investigated using 1, 1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging assay, acetic acid induced writhing inhibition, brine shrimp lethality bioassay and castor oil induced diarrhea inhibition respectively. The extract showed remarkable free radical scavenging activity with an $IC_{50}$ of $27.47{mu}g/mL$. The extract produced significant (P<0.001) writhing inhibition at the doses of 250 mg and 500 mg/kg in acetic acid induced writhing in mice. With the extract, significant lethality to brine shrimp was found with $LC_{50}$ value at $92.79{mu}g/mL$. In antidiarrheal activity test, the extract produced 1.25 h latent period of diarrheal induction and 75.2% inhibition in diarrheal episodes compared to positive standard which showed 1.3 h of latent period and 80.55% inhibition in diarrheal episodes. Different phytoconstituents present in the bark might be responsible for biological activities found with this study. The results of this study support the traditional uses of this plant part and could form the basis of further investigation including compound isolation.