Patients with eclampsia, preeclampsia, chronic hypertensive vascular disease without superimposed toxemia, idiopathic seizures and in normal labor were studied to determine in what respect serum and cerebral spinal fluid (CSF) from eclamptic patients differed from those of other patients relative to concentrations of glucose, protein, calcium, uric acid and hydrogen ion. All eclamptic patients had elevated CSF protein levels. The increase in protein did not appear to be related to the severity of toxemia nor did the extent of the increase differ greatly from one patient to another. Also CSF from most of the eclamptic patients contained red blood cells, the numbers of which were directly related to the severity of the disease. In addition, serum and CSF from most patients with eclampsia characteristically had an abnormally low pH and elevated levels of uric acid and glucose. These studies should provide a more comprehensive means for diagnosing and assessing the condition of eclamptic patients.