Which herb has anticholinergic actions and is used for asthma and muscle spasms?

• A. Ephedra sinica (Ephedra)
• B. Echinacea angustifolia (Echinacea)
• C. Datura stramonium (Jimsonweed)
• D. Digitalis purpurea (Foxglove)

Answer: (C)

Anticholinergic actions block muscarinic receptors, which in the airways reduces bronchoconstriction and secretions, producing bronchodilation and relief of smooth muscle spasm. Datura stramonium contains tropane alkaloids (like atropine) that exert strong antimuscarinic effects, giving both bronchodilation and antispasmodic action. This historic combination made it useful for asthma and for muscle spasms, since relaxing smooth muscle helps open airways and ease cramps. However, its toxicity is significant, with symptoms such as rapid pulse, dilated pupils, confusion, and delirium, so it’s not used clinically today except in very controlled contexts.

The other herbs don’t fit the anticholinergic bronchodilator profile: Ephedra acts via adrenergic (sympathomimetic) pathways to cause bronchodilation, not through anticholinergic blockade; Echinacea is an immune stimulant; Digitalis is a cardiac glycoside affecting heart function, not bronchodilation or antispasmodic smooth muscle.