Hyssop has a long history of medicinal use and was so highly esteemed in the past that it was considered to be a virtual cure-all[254]. Currently an undervalued herb, it is often used as a household remedy, particularly as an expectorant and stomach tonic[4, 254]. It has a positive effect when used to treat bronchitis and respiratory infections, especially where there is excessive mucous production[254]. Hyssop can irritate the mucous membranes, so it is best given after an infection has peaked, when the herb's tonic action encourages a general recovery[254]. The plant should not be used by pregnant women, however, since in large quantities it can induce a miscarriage[7]. The leaves and flowering tops are antiseptic, antitussive, astringent, carminative, diaphoretic, emmenagogue, expectorant, pectoral, sedative, stimulant, stomachic, tonic and vasodilator[4, 7, 9, 21, 165, 238]. The plant can be harvested when in full flower and dried for later use[4]. A tea made from the leaves is used in the treatment of flatulence, stomach-aches, upper respiratory tract infections, coughs in children etc[222, 238]. A poultice made from the fresh herb is used to heal wounds[4, 238]. The essential oil is used in aromatherapy. Its keyword is 'Stability'[210]. This oil should not be used on people who are highly strung as it can cause epileptic symptoms[7, 254]. The essential oil should not be used internally except under professional supervision[254].