With growing public concerns over chemical-free homes, the forest products industry is highly motivated to find environmentally safe alternatives that meet the demands of green construction. One promising wood protection agent is the biopesticide chitosan. Chitosan has pesticidal activity against fungi and some insects, and is inexpensively synthesized from chitin, a waste product of the shrimp industry. Little is known, however, regarding its toxicity to subterranean termites or to the symbionts that live in the termite hindgut. These symbionts (mainly bacteria and protists) play a prominent role in subterranean termite physiology because they digest wood into simpler nutrients that the termite needs to grow on. Results from the Forest Service’s Forest Products Laboratory experiments showed that termites suffered 100 percent mortality when exposed to wood treated with 2 percent chitosan. Moreover, by feeding termites sublethal concentrations of chitosan, it was observed that the 0.5 percent chitosan wood treatment decreased the total number of protist individuals, while the 1 percent chitosan treatment reduced their diversity from ten to just two species. Thus, unlike many synthetic insecticides, where the target is the insect itself, chitosan exerted its toxicity by affecting diversity and abundance of the gut protists. This discovery suggests that the "gut reaction" may be an important target when trying to control termites with environmentally-friendly biopesticides.