In a retrospective study the serum concentrations of calcium and phosphate and the activity of serum alkaline phosphatase in 54 epileptic patients treated by a variety of antiepileptic drugs (group A) were compared with those in 54 non-epileptic control patients (group B). Group B was chosen by computer to assign to each epileptic one control patient of identical sex and age. Patients affected by kidney or liver diseases were excluded from the study. 2. The data showed significantly lower calcium and phosphate concentrations and a higher activity of alkaline phosphatase in group A. Serum phosphate, but not calcium, was inversely correlated to the activity of serum alkaline phosphatase. 3. A minority of the epileptic patients were treated either by diphenylhydantoin or phenobarbital. The serum calcium tended to be lower under the former drug. The combined intake of both drugs produced no further hypocalcemic effect.
