Silkworm droppings are a well-known Chinese herbal medicine. Many people wonder if they are a plant or something else. In fact, silkworm droppings are simply the waste produced by silkworms. Now that's clear. Silkworm droppings can be divided into early and late varieties. Early silkworm droppings are collected in spring, while late silkworm droppings are gathered in autumn.Late silkworm droppings are more effective for medicinal use. Silkworm droppings are typically collected from second- and third-stage silkworms. Next, let's unveil the mystery of silkworm droppings.
Silkworms feed exclusively on mulberry leaves, consuming no other substances. Mulberry leaves are quickly ingested, absorbed, and excreted by the silkworms. Consequently, silkworm droppings contain abundant nutrients. Historical texts document the medicinal use of silkworm droppings for treating wind-cold colds.
Dried silkworm droppings appear as small, short cylindrical pellets measuring 2–5 mm in length and 1.5–3 mm in diameter. Their surface is gray and rough, featuring six distinct longitudinal ridges and 3–4 shallow transverse lines. Both ends are slightly flattened, forming a hexagonal shape. The pellets are hard yet brittle, easily crumbling when exposed to moisture. They emit a faint grassy odor.The finest quality is characterized by dryness, black color, firmness, uniformity, and absence of impurities. Primary production areas include Zhejiang, Sichuan, Henan, Jiangsu, Hunan, Yunnan, Guangdong, Anhui, Gansu, Hubei, Shandong, and Liaoning.
Silkworm sand contains 83.77–90.44% organic matter, 9.56–16.23% ash, and 1.91–3.60% total nitrogen.It also contains chlorophyll, which can be extracted using ethanol or acetone. Reports indicate that silkworm sand from third-, fourth-, and fifth-instar silkworms yields crude chlorophyll at 1.6%, 2.0%, and 2.4% respectively, though only a small portion is true chlorophyll.For instance, crude chlorophyll from fifth-instar silkworm feces contained only 13.19% pure chlorophyll, with the remainder comprising 48.92% saponifiable and 44.45% unsaponifiable components. Silkworm feces also contain 0.25–0.29% phytosterols.Additionally, it contains unsaponifiable components such as β-sitosterol, cholesterol, ergosterol, tetracosanoic acid, and humulesterol. β-Sitosterol-β-glucoside has also been isolated from silkworm feces.
Silkworm sand possesses significant medicinal value. Through long-term experience in combating diseases, coastal communities have developed effective remedies. Residents frequently exposed to sea air often suffer from rheumatism. They treat this condition by boiling one ounce of late-stage silkworm sand into a decoction, divided into three doses. Each dose is consumed with half a cup of warm rice wine, yielding remarkably satisfactory results—a cost-free cure.
This concludes our introduction to silkworm sand. We hope this information proves helpful. Wishing you good health and smooth sailing this winter.