The „Black Plague” pandemic (1347–1351) was a biological and epidemiological phenomenon. The term „red plague” was first used by F. Reinhardt in his work „Die Rote Pest” (1930). The „Red Plague” is a plague of Bolshevik / communist ideological, political and military fanaticism, installed in October 1917 in Russia and later spread to several countries. The origin of these two plagues is totally different; at the same time, there are multiple affinities of imagological, symbolic, ethnological, demographic, demonological and semiotic type between them. The medieval plague appeared simultaneously with Death, Hunger and War, respectively, the communist regimes, associated with the „red plague”, are guilty of mass extermination of tens and even hundreds of millions of people worldwide. The “red plague” has far outweighed its disastrous impact on any plague or pandemic in human history.