This chapter presents an introduction on animal and human bites and scratches. A major concern in all bite wounds is subsequent infection. Approximately, 20% or more of these bites are infected by nearly any group of pathogens. The animal involved and the location of the bites is important. Substantially more dog bites occur than cat bites. These two species account for the majority of (non-human) mammalian bite wounds encountered. Pasteurella species, particularly P. multocida, are Gram-negative cocobacilli that are frequently isolated from wounds after cat and dog bites, scratches or licks. Human bites can be either accidental or intentional and either quite serious or relatively harmless. The potential risk of blood-borne transmission of infection (HIV, HBV, and HCV) following human bite although epidemiologically insignificant, is biologically possible.