Estragole

Estragole, or p-allylanisole or 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 tarragon oil making up 60–75% of the oil. It is also found in basil (23–88%), pine oil, turpentine and Syzygium anisatum.

Estragole is used in perfumes and as a food additive for flavor.

Risks
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.