Brucine is a chemical compound, closely related to strychnine. It is a bitter alkaloid resembling strychnine. It can be found in some plant species, the most well-known variety being the Strychnos nux-vomica tree, found in South-East Asia.

While brucine is related to strychnine it is not as poisonous. If a human consumes over 2 milligrams of pure brucine they will almost certainly suffer symptoms resembling strychnine poisoning.

Brucine does have certain medical uses. It is primarily used in the regulation of high blood pressure, and other comparatively benign cardiac ailments.

It is cultivated commercially in some parts of the United States, and in the European Union.

Perhaps the most well known reference to brucine occurs in "The Count of Monte Cristo", the novel by French author Alexander Dumas: "Well", replied Monte Cristo "suppose, then, that this poison was brucine, and you were to take a milligramme the first day, two milligrammes the second day, and so on."