Prevotella intermedia (formerly Bacteroides intermedius) is a gram-negative, obligate anaerobic pathogenic bacterium involved in periodontal infections, including gingivitis and periodontitis, and often found in acute necrotizing ulcerative gingivitis. It is commonly isolated from dental abscesses, where obligate anaerobes predominate. P. intermedia is thought to be more prevalent in patients with noma. 
P. intermedia use steroid hormones as growth factors, so their numbers are higher in pregnant women. It has also been isolated from women with bacterial vaginosis.