The causes and effects of neuronal degeneration are of major interest to a wide variety of neuroscientists. Paralleling this growing interest is an increasing number of methods applicable to the detection of neuronal degeneration. The fluorescent dye Fluoro-Jade B (FJB), like its more purified brother Fluoro-Jade C (FJC), is an anionic fluorescein derivative useful for the histological staining of neurons undergoing degeneration. Fluoro-Jade B differs from FJC in that it is a slightly less refined chemical formulation and thus it does not quite provide the same level of signal to noise or high resolution as FJC. Nonetheless FJB is still widely used and works very well as a marker of degenerating neurons and even glia (see Damjanac M et al.,?Brain Res.?2007;1128(1):40-9). FJB operates nearly identically in protocol to that of FJC, and Fluoro-Jade B is compatible with several other labeling procedures including immunofluorescent and fluorescent Nissl techniques. Fluoro-Jade B stains all degenerating neurons regardless of specific insult or mechanism of cell death. Fluoro-Jade B exhibits the greatest signal to background ratio, as well as the highest resolution. This translates to a stain of maximal contrast and affinity for degenerating neurons. This makes it ideal for localising not only degenerating nerve cell bodies but also distal dendrites, axons and terminals. The dye is highly resistant to fading and is compatible with virtually all histological processing and staining protocols.