Acute pandysautonomia and acute autonomic and sensory neuropathy were reviewed with special reference to their clinical entity, pathogenesis and clinical course. Since acute pandysautonomia was primarily described as an entity by Young et al. in 1969, a number of similar cases have been described. The disorder is characterized by severe sympathetic and parasympathetic impairment with relative or complete preservation of somatic motor and sensory functions. Some cases have only shown a cholinergic dysautonomia, while others have displayed a loss of autonomic function together with other impairments of nervous function. In 1980, Colan et al. reported a patient with acute autonomic and sensory neuropathy, manifesting severe sensory impairment and dysautonomia with marked loss of myelinated and unmyelinated fibers. Several other similar cases have appeared in the literature. Four years prior to the Colan et al. report, the author described a case which showed almost the same symptoms. At the present time, it is not clear whether this disorder is a new syndrome that is different from acute pandysautonomia or merely a subtype of it. The causes of the above two syndromes are unknown; however, an immunological disorder similar to the Guillain-Barré syndrome has been suggested. The clinical course is often protracted with slow improvement. However, from the author's experience, a relatively rapid improvement occurs after a single systemic administration of either parasympathomimetic or sympathomimetic agonists. Acute pandysautonomia which includes acute autonomic and sensory neuropathy has recently become more common: A number of similar cases have been reported worldwide, including many areas in Japan.