Fluorescein sodium (FL)-guided resection has become an important and beneficial treatment method for malignant brain tumors. FL-guided resection improves the rate of gross total resection in high-grade gliomas (HGG) and cerebral metastases (CM). FL sensitively visualizes the disruption of the blood-brain barrier in the area surrounding malignant lesions, similar to contrast-enhanced T1-weighted MR sequences. This review of the current literature summarizes the history of FL in neurosurgery from 1946 until today. We discuss the molecular mechanism of FL accumulation in cerebral malignant tumors and provide an overview of the current practice of using FL and applying a dedicated surgical microscope filter. Additionally, we outline and discuss ongoing trials and future projects.