Toluene is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a CH3 group attached to a phenyl group. The major use of toluene is as a mixture added to gasoline to improve octane ratings. Toluene is also usedto produce benzene and as a solvent in paints, coatings, synthetic fragrances, adhesives, inks, and cleaningagents. Toluene is also used in the production of polymers used to make nylon, plastic soda bottles, andpolyurethanes and for pharmaceuticals, dyes, cosmetic nail products, and the synthesis of organicchemicals. The CNS is the primary target organ for toluene toxicity in both humans and animals for acute and chronicexposures. CNS dysfunction (which is often reversible) and narcosis have been frequently observed inhumans acutely exposed to low or moderate levels of toluene by inhalation; symptoms include fatigue,sleepiness, headaches, and nausea. CNS depression and death have occurred at higher levels of exposure. Toluene is used in veterinary medicine as a treatment for various parasites in dogs and cats. It is used for the removal of ascarids (Toxocara canis and Toxascaris leonina) and hookworms (Ancylostoma caninum and Uncinaria stenocephala) and as an aid in removing tapeworms (Taenia pisiformis, Dipylidium caninum, and Echinococcus granulosus) from dogs and cats.