This study evaluated, the antidiarrhoeal and antibacterial activity of the methanolic extracts of seed and pulp of Ziziphus mauritania. The crude extracts were prepared by maceration of seed and pulp powder in methanol. The pulp extract was partitioned into n-hexane, ethylacetate, n-butanol and aqueous fractions. The ethylacetate extract was further fractionated by column chromatography into four fractions A-D. The antibacterial activity of the crude extracts, and fractions were evaluated by Agar well diffusion method .The antidiarrhoeal activity of the crude seed and pulp extracts were evaluated using castor oil-induced diarrheal model, charcoal meal test and anti-fluid accumulation test in rats. The result of phytochemical test indicated that tannins, flavonoids, saponin, cyanogenic glycosides, and terpenoids were present in both seed and pulp extracts. The antibacterial susceptibility test showed that the seed and pulp extracts possess inhibitory activity against Staphyloccus aureus, Eschericial coli and Salmonella spp. The fractions obtained from the pulp extract also showed varied antibacterial activity, the diameter of the zone of inhibition obtained ranged from 29-11 and 27-10 mm for seed and pulp respectively. In the castor oil-induced model, fluid accumulation test, the methanolic extracts of the seed and pulp produced a significant (p<0.05) decline in volume of intestinal contents. Results from the charcoal meal test revealed that all the extract produced a significant (p<0.05) anti-motility effect. Based on the findings of this work, the pulp methanolic extract of this plant possess antibacterial and anti-diarrhoeal properties and validates its use in traditional medicine for the treatment of diarrhoea and a number of ailments caused by microorganisms.