The few reported instances of "severe Dilantin (diphenylhydantoih) intoxication have been reviewed, and an additional case, occurring in a young pregnant woman who ingested 21.5 g of Dilantin and 2.4 g of phenobarbital, is recorded. A prolonged period of restless coma ensued, characterized by undulating levels of responsiveness and reflex activity which made evaluation difficult and resulted in postponement of hemodialysis until 138 hours postingestion. Response to dialysis was not dramatic, but the procedure may have prevented further neurologic deterioration. However, improvement was slow and gradual. The intoxication did not appear to affect adversely the infant born after the poisoning.