Silkworm excrement contains 83.77 ~ 90.44% organic matter, 9.56 ~ 16.23% ash and 0/.91~ 3.60% total nitrogen. It also contains chlorophyll which can be extracted with ethanol or acetone. According to reports, crude chlorophyll 1.6, 2.0 and 2.4% were found in silkworm excrement of the third, fourth and fifth instars, but only a small part of real chlorophyll was found. For example, the crude chlorophyll of the fifth instar silkworm excrement only contains pure chlorophyll 13. 19%, and the rest is saponified by 48.92% and unsaponifiable by 44.45%.

Silkworm excrement contains 0.25 ~ 0.29% plant alcohol. It also contains unsaponifiable components β-sitosterol, cholesterol, ergosterol, tetracosanol and hops alcohol. β-sitosterol-β-glucoside was isolated from silkworm excrement.

Silkworm excrement contains leucine, histidine and other 13 free amino acids. With the growth of silkworm larvae, the contents of leucine and histidine in feces are also increasing.

Silkworm excrement contains a lot of carotene. The crude chlorophyll above contains vitamin A3644 international units per gram. Silkworm excrement also contains a lot of vitamin B.

Silkworm excrement contains plant growth hormone-indoleacetic acid.

Silkworm excrement contains copper, and the content reaches the highest value at the fifth instar. Copper is obtained from mulberry leaves, and each gram of fresh mulberry leaves contains copper 1.02 ~ 2.22 micrograms.