We report two cases of severe disorders after spinal puncture with injection of hydrosoluble material. The first case concerned a 36-year-old woman with intrathecal injection of 125 ml of hydrocortisone acetate. An intracranial occipital hematoma developed. The second case concerned a 26-year-old man with intrathecal injection of contrast media and hydrocortisone. A chemical meningitis occurred. In both cases the natural course was favorable. Both complications are well known but rare. A review of the literature is made with description of the mechanisms. Preventive therapeutic measures are reported.