Balsam

Balsam is the resinous exudate (or sap), which forms on certain kinds of trees and shrubs. Balsam (from Hebrew bosem בֹּשֶׂם, "spice", "perfume") owes its name to the biblical Balm of Gilead.

Balsam is a solution of plant-specific resins in plant-specific solvents (essential oils). Such resins can include resin acids, esters, or alcohols. The exudate is a mobile to highly viscous liquid and often contains crystallized resin particles. Over time and as a result of other influences the exudate loses its liquidizing components or gets chemically converted into a solid material (i.e. by autoxidation).

Some authors require balsams to contain benzoic or cinnamic acid or their esters. Plant resins are sometimes classified according to other plant constituents in the mixture, for example as:

Usually, animal secretions (musk, shellac, beeswax) are excluded from this definition.

Some balsams, such as Balsam of Peru, may be associated with allergies. In particular, Euphorbia latex ("wolf's milk") is strongly irritant and cytotoxic.

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