Necrotic tissue is dead tissue, which usually results from an inadequate local blood supply. Necrotic tissue contains dead cells and debris that are a consequence of the fragmentation of dying cells.Necrotic tissue changes color from red to brown or black/purple, as it becomes more dehydrated.ecrotic tissue is dead tissue, which usually results from an inadequate local blood supply. Necrotic tissue contains dead cells and debris that are a consequence of the fragmentation of dying cells.