Internuclear Ophthalmoplegia (INO), a dysfunction of the medial longitudinal fasciculus, is frequently seen in toxic coma (7 out of 70 cases). INO is most often bilateral and can be associated with different stages of coma. Such an association is a strong argument for the toxic etiology of a coma. But INO has no value in determining the source of intoxication and is no prognostic indicator for the outcome.