With antibiotic resistance being an enduring problem worldwide, alternative treatment options, such as 'natural antibiotics', should be considered. This work aimed to perform antimicrobial assays, with the purpose of scientifically evaluating the effectiveness of three Namibian ethno-medicinal plants, namely:!Guxa (Aptosimum albomarginatum Marloth and Engl.), Aru (Albizia anthelmintica A. Rich Brongn.) and Gu-!aru (Dicoma schinzii O. Hoffm.). It was found that !Guxa root extract exerted antimicrobial activity against five out of the eight strains tested, with strong activity against Streptococcus sanguinis at an extract concentration of 20mg/ml. Moderate activity was observed for the other cultures tested. Candida albicans, Escherichia coli and Pseudomonas aeruginosa were resistant to !Guxa. These results give some scientific proof regarding the usefulness of !Guxa root extract as traditional medicine in some instances, thereby generating new knowledge to be shared with fellow researchers. Keywords: Aptosimum albomarginatum, Albizia anthelmintica, Dicoma schinzii, traditional ethno-medicinal plants, antimicrobial activity, Namibia.