The thesis is composed both of ethnopharmacological investigations, screening studies as well as isolation and identification of compounds with specific bioactivities. The ethnopharmacological survey identified more that 100 different plants used in wound healing. Two of those, Entada africana and Trichilia emetica, were chosen for investigation of bioactive pectic polysaccharides in the water extracts. Pectic type polymers were identified as having effect on the complement system. 78 different plant extracts were screened for their antioxidant, free radical scavenging, larvicidal, antifungal and molluscicidal activities. The two plants chosen for further studies were Glinus oppositifolius and Diospyros abbysinica. The first was shown to contain saponins with molluscicidal activity while the second had strong antifungal activities.