Hemlock water dropwort poisoning.

Severe plant poisoning is relatively uncommon in adults. We report two adults who ingested hemlock water dropwort roots, having mistaken them for wild parsnip. One developed prolonged convulsions, severe metabolic acidosis and respiratory distress requiring mechanical ventilation. The toxin--oenanthotoxin--was detected in the gastric aspirate and measured by high performance liquid chromatography.