This review will discuss several intracranial infections and sepsis-associated encephalopathy. Intracranial infections and inflammation of interest to the neurologist and EEG technicians include viral and autoimmune encephalitides; bacterial, fungal, and other meningitides; cerebritis; and brain abscess and subdural empyema. Sepsis-associated encephalopathy refers to a diffuse brain dysfunction secondary to infection that is principally located outside of the central nervous system. It is much more common than all of the intracranial infections put together, at least for adults in Western society. It probably involves a number of mechanisms that are not mutually exclusive and likely vary from patient to patient. Morbidity and mortality are directly related to the severity of SAE. The earliest features of SAE are delirium and mild EEG slowing; it is crucial to recognize these early features and to search for and treat the underlying infection promptly to reduce mortality and morbidity.