Scriptaid is a histone deacetylase inhibitor that has an optimal concentration of 6-8 μM in a cell-based assay, is less toxic than trichostatin A, and works in a wide variety of biological systems. It induces cell cycle arrest in colon cancer cells in culture and inhibits tumor growth in vitro and in vivo. Scriptaid also facilitates the cloning of inbred mouse strains produced by somatic cell nuclear transfer.