Whole plant, especially the leaves and flowers.3
Supportive treatment.
Shrubs, 1–2(–3) m tall, much-branched. Leaves alternate, spirally arranged, thickly papery; leaf blades 1.5–5.5 × 1.0–2.2 cm, apex with a blunt point, strigose on both surfaces. Inflorescence 1–2(–3)-flowered. Corolla bright red, 3.5–4.5 cm in diameter, 3–3.5 cm deep, funnel-shaped, with dark red dots on posterior lobes. Capsules 7–9 × 3–5 mm, strigose. Seeds 1.2–1.5 × 0.3–0.4 mm, elliptic.9
Uses in TCM—flowers: harmonise blood, regulate menstruation, suppress cough, dispel wind-dampness, expel toxin and heal furuncles; roots: harmonise blood and stanch bleeding, dispel wind, resolve swelling and relieve pain; fruits: activate blood and relieve pain. Recommended dose: flowers 9–15 g, roots 15–30 g, fruits 1–2 g.2,10
In 2008, a 57-day-old infant presented with vomiting, muscle twiching, cyanosis and loss of consciousness after being fed with formula milk prepared with a decoction of "red flower" for airway problems. He required intubation and mechanical ventilation. He later improved and was discharged 8 days after admission. The "red flower" was later confirmed to be R. simsii. In 2013, a middle-aged woman presented with facial numbness, blurring of vision and hypotension after ingesting several pieces of Rhododendron petals. She improved with supportive treatment and was discharged the next day. In both cases, grayanotoxin III was detected in both urine and plant specimens.8
Grayanotoxins I, II and III can be detected by GC-MS and LC-MS/MS.11,12
