Hash oil or cannabis oil is an oleoresin obtained by the extraction of cannabis or hashish. It is a cannabis concentrate containing many of its resins and terpenes – in particular, tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids. Hash oil is usually consumed by smoking, vaporizing or eating. Preparations of hash oil may be solid or semi-liquid colloids depending on both production method and temperature and are usually identified by their appearance or characteristics. Color most commonly ranges from transparent golden or light brown, to tan or black. There are various extraction methods, most involving a solvent, such as butane or ethanol.
Hash oil is an extracted cannabis product that may use any part of the plant, with minimal or no residual solvent. It is generally thought to be indistinct from traditional hashish, at-least according to the 1961 UN Single Convention on Narcotic Drugs that defines these products as "the separated resin, whether crude or purified, obtained from the cannabis plant".
Hash oil may be sold in cartridges used with pen vaporizers. Cannabis retailers in California have reported about 40% of their sales are from smokeable cannabis oils.