Dong Gua Zi (Ren)

Dong Gua Zi (also called Dong Gua Ren) is the seed of Benincasa hispida (Thunb.) Cogn. (Cucurbitaceae), the wax gourd or winter melon, a vigorous annual climbing or trailing vine cultivated throughout China, India, and tropical Asia. Stems are stout, ridged, and densely hispid, bearing branched tendrils and large, palmately 5–7-lobed leaves 10–25 cm across with hispid surfaces. Solitary, large yellow flowers give rise to an oblong-cylindric to ovoid fruit 30–60 cm long covered in coarse hairs when young and developing a thick, whitish, waxy bloom at maturity. Inside the firm white flesh lie numerous flat, ovate, cream to pale brown seeds 10–15 mm long with a narrow marginal ridge. Ripe fruits are split in late autumn, the seeds washed, dried, and lightly stir-fried. In TCM they cool the Lung, clear phlegm, and discharge pus, and are a key ingredient of classic formulas such as Wei Jing Tang.