Sodium 4-Phenylbutyrate is widely used in biomedical research and clinical applications due to its role as a histone deacetylase (HDAC) inhibitor. It helps regulate gene expression by increasing histone acetylation, which can reactivate silenced genes, particularly those involved in cell cycle control and apoptosis. This property makes it a candidate for studying cancer therapies, especially in neuroblastoma, leukemia, and solid tumors. It is also used in the treatment of urea cycle disorders, where it acts as a nitrogen scavenger, helping to remove excess ammonia from the body by providing an alternative pathway for nitrogen excretion. This application is especially important in genetic conditions like urea cycle defects. In neurodegenerative disease research, Sodium 4-Phenylbutyrate shows promise in reducing protein misfolding and endoplasmic reticulum stress. It has been investigated in models of Huntington’s, Alzheimer’s, and Parkinson’s diseases for its ability to improve cellular protein handling and promote neuronal survival. Additionally, it exhibits anti-inflammatory properties and is explored for use in chronic inflammatory and autoimmune conditions. Its ability to cross the blood-brain barrier enhances its potential for treating central nervous system disorders.