Which herb is used for respiratory conditions and has the root as the part used, containing alantolactone?

• A. Hyoscyamus niger
• B. Iris versicolor
• C. Inula helenium
• D. Juglans nigra

Answer: (C)

The herb used for respiratory conditions with the root as the part used that contains alantolactone is Inula helenium, known as elecampane. The root is the part traditionally used, and it contains alantolactone in its essential oil. Alantolactone contributes antimicrobial and anti-inflammatory effects, helping to loosen and clear mucus and soothe irritated airways, which supports relief from coughs, bronchitis, and other chest infections. Hyoscyamus niger, Iris versicolor, and Juglans nigra are not the standard respiratory-root remedies with alantolactone content; they have different primary uses and constituents.