Rumex nervosus is a plant found and used in Saudi Arabia as traditional herbal medicine. Various types of plant extracts with inherent synergistic properties are being used against oral diseases. Thus, in the present study, the anti-microbial activity of Rumex nervosus extracts was studied against six common oral pathogenic bacterial strains and a pathogenic fungus. Plants of R. nervosus were collected and air-dried, and extracts from various plant parts were obtained. Six clinical isolates of bacteria, namely Staphylococcus aureus, Streptococcus mutans, S. salivarius, S. sanguis, E. faecalis, and Lactobacillus acidophilus), and one pathogenic Candida (C. albicans) were obtained. Antibacterial and antifungal activity of R. nervosus was determined using the Kirby-Bauer agar disc diffusion method. Zones of inhibition were recorded after 48 h of incubation. Data collected were analyzed. A two-way analysis of variance (ANOVA) was applied. P < 0.05 was considered statistically significant. Methanol extract from leaves were highly effective against S. aureus, with a mean inhibition zone of 33 mm, followed by a 28-mm zone of inhibition using an extract from roots and a minimum inhibition zone using an extract from stems. Zones of inhibition using methanol extract from roots were effective against S. mutans, S. sanguinis, E. faecalis, and L. acidophilus, with mean inhibition zones being 19, 17, 33, and 31 mm, respectively. The study has provided insight into a new potential herbal anti-microbial agent that may benefit dental care.