'Vitamin B' was a German unrealised plan by the headquarters of General Ernst-Eberhard Hell’s VII Corps of Generaloberst Hermann Hoth’s 4^th Panzerarmee, part of Generalfeldmarschall Erich von Manstein’s Heeresgruppe 'Süd', for an initial follow-on attack for the southern element of 'Zitadelle' (5 July 1943).

Intended as the exploitation of the 4^th Panzerarmee's expected initial success, the undertaking was to be launched two days later as the means of securing a breakthrough between Sumy and Snagost with the object of destroying the forces of General Nikolai F. Vatutin’s Voronezh Front concentrated in the area around Sudzha.