Endoscopic intraventricular findings using an encephaloscope in 30 cases of ventriculitis and 60 cases of intraventricular hemorrhage were reviewed. In cases of ventriculitis, encephaloscopic findings were classified into 4 stages, early (initial) stage, advanced stage, late (end) stage and recovery stage. Characteristic findings of the early stage were as follows : fibrin and debris floating in light yellowish or whitish turbid CSF and covering ventricular walls and whitish discolored choroid plexus. In the advanced stage, usually xanthochromic or turbid CSF without floating material and lusterless discolored wall with increased and dilated small vessels, sometimes pus or membranous material covering the ventricular wall and choroid plexus. In the late stage, watery clear CSF without floating material, and markedly dilated ventricles associated with enlarged Foramen of Monro. Characteristic abnormal substances were found in 17 of 30 cases, namely, string-like, rope-like, column-like, or membranous and quite often septal formation (septation) or multilocular cavitation (8 cases). In the recovery stage, after treatment, watery clear CSF with normal pressure and normal-sized ventricle, with few exceptions. Cases of intraventricular hemorrhage with bloody CSF and high pressure had not always poor prognosis if not associated with clot, but if the Foramen of Monro was closed by a hard clot which was not easy to remove or suck out, the prognosis was usually poor. Sometimes endoscopic investigation revealed preforated holes from thalamic hemorrhage, intraventricular vascular tumor or arteriovenous malformation. Experience with 18 cases of continuous intraventricular irrigation (CIVI) therapy for ventriculitis and intraventricular hemorrhage was also reported. Newly manufactured artificial CSF had been used since 1974, in a daily dose of 1, 000 to 1, 500 ml depending on the ventricular size. The dose of antibiotics using CIVI was 5-10 times more than that of one intraventricular injection. Duration of CIVI was 4 days to 2 weeks depending on the intraventricular conditions. Clinical safety and usefulness of CIVI with the artificial CSF was discussed.