One of the chemicals routinely used as a performance-enhancing additive in gasoline. Also known as methylbenzene or phenylmethane, it is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent.

Like other solvents, toluene is also used as an inhalant drug for its intoxicating properties.