Toluene also known as toluol, is an aromatic hydrocarbon. It is a colourless, water-insoluble liquid with the smell associated with paint thinners. Toluene is predominantly used as an industrial feedstock and a solvent (paint thinners, nail polish remover, glues, and correction fluid).

Toluene is used in making paints, paint thinners, fingernail polish, lacquers, adhesives, inks, degreasers, and rubber and in some printing and leather tanning processes. It also has many uses in other industries. In the explosives industry, it is essential in making the flammable, explosive compound known as TNT or trinitrotoluene. In the plastics industry, it is a component in the manufacturing of nylon and plastic bottles. Hair dyes and nail products include toluene, as well, utilized by the cosmetics industry.