In Japan, 9 cases of severe lithium intoxication have been treated by hemodialysis so far, and the usefulness and indications of this procedure are not yet understood fully. We have recently experienced a case of lithium intoxication treated by hemodialysis. Considering this case together with those reported previously, we have prepared some preliminary guidelines for the application of hemodialysis to patients with lithium intoxication. The blood concentration of lithium, renal function, the severity of consciousness disturbance and clinical symptoms such as somatic complications are, of course, important indices for the application of this therapy. We think that the signs of intoxication and the time interval between the onset and the beginning of treatment also serve as useful indices for application of hemodialysis.