The study was conducted to reveal and document ethnobotanical knowledge and practices of traditional healers in selected sites of Eastern Hararghie. Ethnobotanical data were collected using semi-structured interviews and field observation from 9 traditional healers in 4 study sites of Eastern Hararghie. Data were collected, quantified and summarized using graphs, tables and different ranking techniques. The study revealed 32 medicinal plants species belonging to 31 genera and 25 families. The plants were used to treat 17 major human and animal ailments, 81% used for the treatment of human disorders while the remaining 19% for both. Of the reported species 44% were herbs, and 28 % each were shrubs and trees. Leaf was the most frequently used plant part accounting 62%, followed by fruit (16%) and root (16%). Oral administration was the most commonly used route (60%), followed by topical (31%) route. The most preferred solvent added during the preparation of medicinal plants was water (50%), while 38% of the plant remedies used without any solvent. Fidelity value analysis indicated that Allium sativum L. (83.3%), Gomphocarpus integer N.E.Br (80%), Punica granatum L. (75%) and Cordia africana L. (75%) were the most preferred species used for the treatment of abdominal pain, febrile illness, evil spirit and skin lesions, respectively. Moreover, Allium sativum L. was the first ranked medicinal plant used for the treatment of abdominal pain followed by Vernonia amygdalina Del. and Cucurbita pepo L. This study suggested that traditional healers in eastern Hararghie zone have profound ethnobotanical knowledge and practices.

Medicinal plants are used as a primary means of tackling different ailments especially in developing countries. In the present study, the leaves of Rumex nervosus, Plantago lanceolata, Lepidium sativum and Solanum incanum were collected and extracted by maceration method using 70% methanol. The extracts were concentrated and the yields recorded. Antibacterial effects of the extracts were tested on selected bacteria such as Streptococcus, S. aureus, L. monocytogenes, E. coli, and Salmonella which were obtained from Haramaya University, Veterinary Microbiology Laboratory. Preliminary screening test for the extract was made using agar disc diffusion method and subsequently the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by agar dilution assay based on the zone of bacterial growth inhibition. The finding indicated that Rumex nervosus showed have the highest zone of inhibition (20mm) against the genus Salmonella followed by Plantago lanceolata with the zone of inhibition (16mm) against L. monocytogenes. On the other hand, Lepidium sativum and Solanum incanum did not have any antibacterial activity against all the cultured bacteria. The minimum inhibitory concentration and the minimum bactericidal concentration of Rumex nervosus against S. aureus were 1.56x103μg/ml and that of Plantago lanceolata against L. monocytogenes were 6.25 x103μg/ml and 1.25 x 104μg/ml, respectively. From the findings it can be concluded that Rumex nervosus and Plantago lanceolata have shown to be a better antibacterial activity against selected bacterial pathogens, while leave extracts of other medicinal plants do not have any effect. Fractionated components of the plants might show better effect which needs further investigation using different solvent and standard medium.Keywords: Agar disc diffusion, Antibacterial activity, Rumex nervosus, Plantago lanceolata, Solanum incanum, Lepidium sativum