A survey is given of the most important findings in respect of iatrogenic damage to the nervous system on the basis of published reports and the author's own findings, taking special account of lumbar puncture and suboccipital puncture, myelography, contrast-medium encephalography, ventriculography and cerebral angiography. The possibility of damage such as the danger of embolism in diagnostic and therapeutic vascular puncture is referred to. Among the lesions caused in the course of therapy, the side-effects of treatment with drugs, effects of radiation, effects resulting from anesthesia, sequelae of neural therapy and of manual manipulations, sequelae of operations, and postvaccinal encephalopathies are discussed. The necessity of systematic morphological examinations for exact assessment of ioatrogenic lesions is stressed. Iatrogenic damage due to neglect of diagnostic and therapeutic measures is also considered.