Cell suspension consisting of cells from immature nervous and hemopoietic tissues was transplanted subarachnoidally to patients with craniocerebral injury aftereffects. In some patients cell therapy led to immune sensitization to donor antigens, detected by the leukocyte migration inhibition test. No signs of tissue-destructive autoimmune reactions were detected in patients receiving cell therapy. Follow-up of 56 patients showed that cell therapy was associated with significant improvement of the neurological status. No serious complications of this treatment modality were observed. Presumably, cell therapy is a safe method which can be used in the treatment of craniocerebral injury aftereffects.