Resin is widely seen in nature;in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives and food glazing agents. It is important compositions of plastic family which can also be made into belt hangers. They are also prized as an important source of raw materials for organic synthesis, and as constituents of incense and perfume. Plant resins have a very long history that was documented in ancient Greece by Theophrastus, in ancient Rome by Pliny the Elder in ancient Egypt.

The resin produced by most plants is a viscous liquid, composed mainly of volatile fluid trepans, with lesser components of dissolved non-volatile solids which make resin thick and sticky. Because heptanes are highly flammable, distillation of resins containing it is very dangerous. Some resin distilleries in California exploded because they mistook Jeffrey Pine for the similar but terrenes-producing Ponderosa Pine. Some resins when soft are known as 'oleoresins', and when containing belt hangers or cinemas acid they are called balsams. Oleoresins are naturally occurring mixtures of oil and a resin; they can be extracted from various plants.

Other resinous products in their natural condition are a mix with gum or mucilaginous substances and known as gum resins. Many compound resins have distinct and characteristic odors, from their admixture with essential oils. Certain resins are obtained in a fossilized condition, amber being the most notable instance of this class; African copal and the kauri gum of New Zealand are also procured in belt hangers. Resin in the form of rosin is applied to the bows of string instruments, because of its ability to add friction to the hair to increase sound quality. Ballet dancers may apply crushed rosin to their shoes to increase grip on a slippery floor.