Herrings kippered by smoking and salting until they turn reddish-brown, i.e. a "red herring". Prior to refrigeration kipper was known for being strongly pungent. In 1807, William Cobbett wrote how he used red herrings to lay a false trail, while training hunting dogs—an apocryphal story that was probably the origin of the idiom.

A red herring is something that misleads or distracts from a relevant or important issue.^[1]It may be either a logical fallacy or a literary device that leads readers or audiences towards a false conclusion. A red herring might be intentionally used, such as in mystery fiction or as part of rhetorical strategies (e.g. in politics), or it could be inadvertently used during argumentation.

The origin of the expression is unknown. Conventional wisdom has long supposed it to be the use of a kipper (a strong-smelling smoked fish) to train hounds to follow a scent, or to divert them from the correct route when hunting; however, modern linguistic research suggests that the term was probably invented in 1807 by English polemicist William Cobbett, referring to one occasion on which he had supposedly used a kipper to divert hounds from chasing a hare, and was never an actual practice of hunters. The phrase was later borrowed to provide a formal name for the logical fallacy and literary device.