Several scale insects, the most common being Kerria lacca, secrete a dark maroon resinous liquid. The insects infect a host tree. When they give off their secretion, they are brushed off the branches and crushed. The colorant is inside the insects, and, when processed, the secretion produces shellac. The Japanese imported their lac from China to stain ivory or wood or to dye fabric. Lac was also used as a medicine to treat circulation problems and clotting.