Intra-arterial ATP infusions with glucose and hyaluronidase were successful in 267 patients suffering from various inner ear disturbances but particularly in sudden deafness. Good clinical results were noted not only in early-treated but also in later cases. Recently, we have also used ATP with hyperbaric oxygen, being successful in cases which were previously treated without improvement. Investigations in guinea-pigs, using artificial hypoxia as a model for human sudden deafness failed because the patterns are not the same. So long as an increase of ATP in the cochlear cells cannot be demonstrated after the i.a. infusions, only an unspecific mechanism can be held responsible for the undoubted clinical successes.