In most developing countries, rainwater is used by many people to meet their water needs. Many Bacillus species known to be harmful to humans have also been identified in rainwater samples. Improving the microbiological quality of the rainwater using modern techniques seems expensive in rural areas for poor people. Extracts from several medicinal plants are often used in rural areas to treat certain bacterial infections. Water and alcohol are often used in traditional therapy to extract the principles of medicinal plants. But little is known about their functional differences or similarities. This study aims to assess the effects of aqueous and hydro-ethanolic leaf extracts of Moringa oleifera Lam on the cultivability of Bacillus cereus and Bacillus thuringiensis isolated from rainwater. Leaf extracts of concentrations 2, 1.5, 1 and 0.5 g/L in contact with cells were incubated at 23°C and 37°C for 3 h, 6 h, 9 h and 24 h. The results showed a decrease in cultivable cells abundance. In most cases, cell abundances between the aqueous extract and hydro-ethanolic extract were not significantly different (P>0.05). A significant difference (P<0.05) was noted amongst cell abundances from each incubation period to another. The effectiveness of each extract for cell inhibition was evaluated and then expressed as a decrease percentage in the number of cultivable cells. A decrease in cultivable B. thuringiensis abundance varied from 75.09 to 99.68% in hydro-ethanolic extract and from 70.75 to 97.94% in aqueous extract. That of B. cereus varied from 0 to 98.86% in hydro-ethanolic extract and from 41.09 to 92.20% in the other. This difference could be linked to the differences in the cell species intrinsic properties. It could also be linked to the presence of some compounds identified. Some of these compounds would act as nutrients for cell growth, counterbalancing cell inhibition caused by others that have antimicrobial effects.