Table 2. Principal medicinal plants used to support expectoration or used to suppress coughs and corresponding herbal drugs and main constituents.

All data from ref. Nagy, Mučaji & Grančai (2017).

Plant	Plant parts, herbal drug	Main constituents
Herbs used to support expectoration
Pimpinella anisum L.	fruit, Anisi fructus essential oil, Anisi aetheroleum	trans-anethole, anisaldehyde
Eucalyptus globulus Labill.	leaf, Eucalypti folium essential oil, Eucalypti aetheroleum	1,8-cineole (eucalyptol), limonene
Foeniculum vulgare var. dulce Mill. or Foeniculum vulgare var. vulgare Mill.	fruit, Foeniculi amari fructus fruit, Foeniculi dulcis fructus essential oil, Foeniculi amari fructus aetheroleum	trans-anethole, fenchone, estragole trans-anethole, fenchone, estragole
Hedera helix L.	leaf, Hederae folium	hederacosides (e.g., hederasaponin C)
Glycyrrhiza glabra L. or Glycyrrhiza uralensis Fisch. or Glycyrrhiza inflata Bat.	root, Liquiritiae radix	glycyrrhizin, glycyrrhizic acid, glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, glabridin
Marrubium vulgare L.	aerial part, Marrubii herba	premarrubiin, marrubiin
Mentha × piperita L.	essential oil, Menthae piperitae aetheroleum	menthol, menthone, menthyl acetate
Primula veris L. or Primula elatior (L.) Hill	flower, Primulae flos root, Primulae radix	saponins
Thymus vulgaris L. or Thymus zygis L.	aerial part, Thymi herba essential oil, Thymi aetheroleum	thymol, carvacrol
Herbs used to suppress cough
Althaea officinalis L.	root, Althaeae radix leaf, Althaeae folium	mucilage
Cetraria islandica (L.) Acharius	thallus, Lichen islandicus	lichenan, isolichenan
Pelargonium sidoides DC or Pelargonium reniforme Curt.	root, Pelargonii radix	tannins, coumarins
Plantago lanceolata L.	leaf, Plantaginis lanceolatae folium	mucilage, iridoids