Parts used:  Leaves and flowering tops

Constituents: Tropane alkaloids (0.045%-0.14%):  hyoscyamine, hyoscine [scopolamine]

Medicinal actions: Antispasmodic, anodyne, sedative, mydriatic

Medicinal use: Hyoscyamus is often compared to Belladonna as both plants exert anticholinergics effects. Hyoscyamus is most often used for its antispasmodic effects on the digestive and urinary tracts, (eg. kidney stones) with large doses affecting the central nervous system.

Pharmacology: 

• Tropane alkaloids (hyoscyamine & scopolamine) are negatively cholinergic & positively adrenergic (sympathomimetic), causing an inhibition of parasympathetic and stimulation of sympathetic nerves via competitive inhibition of acetylcholine. Effects lead to increased intraocular pressure & dipolpia, reduction of bodily secretions, inhibition of vagus nerve (tachycardia, increased cardiac output and raised blood pressure), reduced tone in all smooth muscles: vasodilation, bronchial dilation, reduced peristalsis.

Pharmacy:  Tincture (1:10, 45%), take 10 drops twice a day to a max of 1 ml. Increase by 1 drop every three days until dry mouth and visual disturbances appear. Reduce by 1 drop each day until side effects disappear. Weekly max 10ml.

Toxicity: First sign of toxicity is dry mouth & eyes. Acute: Facial dryness, nausea, increased pulse rate, vertigo, dull headache, dilated pupils, muscular weakness, reduced peristalsis, tachycardia, paralysis, delirium and hallucinations, coma, spasms, cramps, convulsions, rapid pulse, salivation, death. Chronic: macular rash which is dry and pruritic.