This study has been performed on three traditional plant commonly used by healers and country peoples: Aframomum sulcatum, Polyalthia suaveolens, and Pentadiplandra brazzeana. Essential oils have been obtained by hydrodistillation. The bacterial activities have been done on four Bacillus strains and their spores: Bacillus stearothermophilus CNCH 5781, Bacillus subtilis NCTC 3610, Bacillus cereus F3748 and Bacillus megaterium 8174. The methods used for the tests were disc methods on solid medium for the determination of the inhibition diameters and method of dilution in liquid medium for the determination of the CMI, CMB for vegetative cells. The thermal activation of spores has been carried on by using the activation of spore by incubation at appropriate temperature. The results on vegetative cells showed that essential oil from P. brazzeana roots was more active than other by complete inhibition of bacterial growth. The inhibition diameters of P. suaveolens and A. sulcatum essential oils varies between 11.3 ± 1.1 and 19.6 ± 0.5. The determination of MIC and MBC showed that P. brazzeana essential oil had the smallest values. A. sulcatum and P. suaveolens are bacteriostatics on all the strains however P. brazzeana is bactericid on B. cereus, B. megatérium, B. subtilis and bacterostatic on B. stearothermophilus where as Gentamicine was bactericid against all strains. Concerning the capability to inhibit spore growth, the study showed a very strong activity of P. brazzeana essential oil which showed a decrease in the number of colonies of 46 %, 63 %, 56 % and 65 % respectively upon B. cereus, B. substilis, B. megaterium and B. stearothermophilus.