Rheumatoid Arthritis (RA) is a chronic inflammatory disorder of the joints which afflicts 0.5 - 1 % of the world’s population, with approximately three times as many women affected as men. The causes of RA are poorly understood although it is generally accepted that it is an autoimmune disorder triggered by microbial infection (particularly by Proteus spp.). Whilst there is currently no known cure for RA, a wide variety of bushfoods and herbal remedies may be used in traditional medicine to treat (RA) and inflammation. Ninety five extracts from 38 Australian bushfood plant species with a history of ethnobotanical usage were investigated for their ability to control the microbial trigger for RA (P. mirabilis). Fifty six of the extracts (58.9 %) inhibited the growth of P. mirabilis. Extracts of candlenut, camphorwood, quinine tree leaf, gumbi gumbi, Brush cherry and riberry fruit and Tasmanian pepper peppercorn and leaf were particularly effective Proteus inhibitors. All extracts with Proteus inhibitory activity were also either non-toxic, or of low toxicity in the Artemia nauplii bioassay. The low toxicity of these extracts and their inhibitory bioactivity against Proteus spp. indicate their potential for blocking the onset of rheumatoid arthritis.