中性红是一种组织学复染色染色剂，可用来为溶酶体、 高尔基体和尼斯尔氏粒染色。同时也是酸碱指示剂。

中性红也是一种活体染剂，因为随着细胞逐渐死亡，它们吸收中性红的能力也会变差。

Neutral red (toluylene red, Basic Red 5, or C.I. 50040) is a eurhodin dye used for staining in histology. It stains lysosomes red. It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons.