The salivary microbiome consists of the nonpathogenic, commensal bacteria present in the healthy human salivary glands. It differs from the oral microbiome which is located in the oral cavity. Oral microorganisms tend to adhere to teeth. The oral microbiome possesses its own characteristic microorganisms found there. Resident microbes of the mouth adhere to the teeth and gums. "[T]here may be important interactions between the saliva microbiome and other microbiomes in the human body, in particular, that of the intestinal tract."

Haemophilus is a genus of Gram-negative, pleomorphic, coccobacilli bacteria belonging to the family Pasteurellaceae. While Haemophilus bacteria are typically small coccobacilli, they are categorized as pleomorphic bacteria because of the wide range of shapes they occasionally assume. These organisms inhabit the mucous membranes of the upper respiratory tract, mouth, vagina, and intestinal tract. The genus includes commensal organisms along with some significant pathogenic species such as H. influenzae—a cause of sepsis and bacterial meningitis in young children—and H. ducreyi, the causative agent of chancroid. All members are either aerobic or facultatively anaerobic. This genus has been found to be part of the salivary microbiome.