Oil of sassafras is toxic in doses as small as 5 ml in adults. 21 Ingestion of 1 tsp (5 ml) produced shakes, vomiting, high blood pressure and pulse in a 47-year-old female. 22 Another case of a 1 tsp dose of sassafras oil in a young man also caused vomiting, along with dilated pupils, stupor and collapse. 4 There have been additional reports of the oil being fatal, 5 causing abortion 4 and causing liver cancer. 1 , 4 , 5 Safrole is a potent inhibitor of liver microsome hydroxylating enzymes; this effect may result in toxicity caused by altered drug metabolism. 19 Aqueous and alcoholic extracts of root bark can cause a range of effects in mice, inducing ataxia, ptosis, hypersensitivity to touch, CNS depression and hypothermia. Symptoms of sassafras oil poisoning in humans may include vomiting, stupor, lowering of body temperature, exhaustion, tachycardia, spasm, hallucinations, paralysis and collapse. 1 , 5