The volatile oil is considered an irritant topically and can cause nausea and vomiting, headache, dizziness, convulsions, cardiac or respiratory arrest if taken internally. As such, the crude herb is considered far safer.
Contact dermatitis reactions have been reported with topical.
Thyme may induce enzymes in phase one and two detoxification in the liver (Sasaki et al 2005). The clinical significance of this is unknown.
Contraindications and Precautions
Contraindicated in people who are allergic to the Labiatae family of plants. Other cautions are gastritis, enterocolitis and congestive heart failure.
Essential oil not recommended in pregnancy.