Topic was a chocolate bar made by Mars, Incorporated in France and sold throughout Europe. It contained hazelnuts, nougat and caramel.

The bar was first introduced in 1962. In the UK, it was advertised with the line "A Hazelnut in Every Bite".^[1]

In 1997, a Topic bar was found to have contained the remains of a mouse, a subsequent court case ruled that Mars could not be found guilty of negligence under the Food Safety Act, due to the mouse originating from a supplier in Turkey, and the fact that Mars had been diligent in checking the Turkish operation.^[2]

The chocolate bar was promoted in a series of radio advertisements broadcast in 2002 with the strapline "A joy to eat, but a bitch to make".^[3][4] These adverts featured actors Simon Pegg and Mark Heap who both appeared in the cult British TV comedy Spaced.

The bar was removed from boxes of Celebrations in 2006, along with Twix (although Twix has subsequently been reintroduced).

In 2022 Mars, Incorporated ceased production of the Topic.^{[citation needed]}.