Scriptaid (1 µg/mL) treatment inhibits cell growth in breast cancer cell lines, results in increased accumulation of both acetyl H3 and acetyl H4 proteins in MDA-MB-231, MDA-MB-435, and Hs578t cells. Scriptaid also inhibits cell growth of MDA-MB-231, MDA-MB-435, and Hs578t cell lines, with IC50s of 0.5-1.0 µg/mL. Scriptaid (0.1-1.0 µg/mL) induces ER and PR mRNA expression in a dose dependent manner; when it is combined with AZA, they enhance ER expression and induce a functional ER protein. Scriptaid and SAHA preferentially inhibit the Class I histone deacetylases, hdac1, 2, and 3. Scriptaid is a potent anti-T. gondii compound with low cytotoxicity, and the IC50 is 39 nM. Scriptaid has atypical effects in T. gondiiinfected HS68 cells. Scriptaid inhibits the growth of HeLa cells with IC50 of 2 μM at 48 h in a dose-dependent manner. Scriptaid also affects cell-cycle and apoptosis.