1 Twenty patients, aged eight to 14 years, were admitted to hospital over a six year period with an acute encephalopathy following toluene abuse. 2 In all cases toxicity was confined to the central nervous system. Electroencephalography performed in ten patients was abnormal in three. 3 Fourteen patients made a complete recovery, five had evidence of personality impairment but were lost to follow-up, one had a persistent cerebellar ataxia one year after admission, despite absence of exposure to toluene. 4 Solvent abuse may be impossible to establish on history, as in six of these patients. Blood assay of toluene is vital in such cases, as is an awareness that toluene abuse may lead to acute encephalopathy.