The parotid gland is most commonly involved in bacterial sialadenitis. Predisposing factors for the ductally ascending infection, are dehydration, xerogenic drugs and salivary gland diseases associated with ductal obstructions or reduced saliva secretion. In the majority of cases the infection is caused by Staphylococcus aureus. However, a variety of other aerobic and anaerobic pathogens may be involved. Besides hydration, elimination of ductal obstruction and stimulation of saliva flow antibiotic treatment according to antibiogram is essential. In selected cases, for instance if a salivary gland abscess develops, surgical treatment may become necessary. Actinomycosis, tuberculosis and atypical mycobacteriosis are rare variations of bacterial sialadenitis which clinically may resemble a salivary gland tumor.