The sodium salt of butyrate with potential antineoplastic activity. Butyrate, a short chain fatty acid, competitively binds to the zinc sites of class I and II histone deacetylases (HDACs). This binding affects hyperacetylation of histones, resulting in a modified DNA conformation, which subsequently leads to the uncoiling or relaxing of chromatin. Enhanced accessibility of chromatin to transcription-regulatory complexes leads to increased transcriptional activation of various epigenetically suppressed genes. Butyrate, a HDAC inhibitor, induces cell cycle arrest in G1 or G2/M and also increases the expression of other genes and proteins involved in cellular differentiation and apoptotic signaling.