Estragole

Estragole (p-allylanisole, methyl chavicol) is a natural organic compound. Its chemical structure consists of a benzene ring substituted with a methoxy group and a propenyl group. Estragole is a double-bond isomer of anethole. It is a colorless to pale yellow liquid. It is the primary constituent of essential oil of tarragon, making up 60–75% of the oil. It is also found in essential oils of basil (23–88%), pine oil, turpentine, fennel, anise (2%), and Syzygium anisatum.
Estragole is used in perfumes and as a food additive for flavor. It is described in the flavors trade as "strong, sweet, tarragon"
Estragole is suspected to be carcinogenic and genotoxic, as is indicated by a report of the European Union.A reduction in consumption is thus recommended. Special care is also to be taken with infant nourishment, since many teas or tea-like beverages contain estragole.