CSF beta--glucuronidase, polyamines and carcinoembryonic antigen (CEA) were analyzed in 16 patients with meningeal carcinomatosis from solid tumors in systemic organs, 27 with benign brain lesions, 11 with primary brain tumors, 14 with metastatic brain tumors and 5 with leptomeningeal dissemination of other malignant diseases. beta--glucuronidase levels in all cases of meningeal carcinomatosis, meningeal gliomatosis and meningeal lymphoma were higher than 100 micrograms/dl/hr. On the other hand, levels in all cases of benign brain lesions were below 100 micrograms/dl/hr. Levels of beta--glucuronidase in the cases of metastatic brain tumors returned to normal levels after tumor resection. Levels of beta--glucuronidase and polyamines were not high in the cases with positive cytology in CSF after tumor resection. The polyamine level seemed to be dependent on the growth rate of the disease and was shown to below 0.05 nmol/ml in all cases after resection of the metastatic brain tumors. Cystic fluid of both benign and malignant tumor showed high levels of beta--glucuronidase and polyamines except for spermidine and spermine levels in a suprasellar cyst. Some cases of meningeal carcinomatosis with high levels of serum CEA did not always show high levels of CSF CEA. In the surgical cases with a metastatic brain tumor, the cases with leptomeningeal, especially dural attachment showed high levels of beta--glucuronidase and CEA preoperatively, but they returned to normal after surgery. In 2 cases of meningeal carcinomatosis treated by intrathecal chemotherapy with MTX and Ara-C, CSF beta--glucuronidase and CEA showed clinical condition better than the cell count in CSF decreased rapidly following chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)