Ionic liquids (ILs) have been exploited to improve the absorption of poorly water-soluble drugs. Custom-made ILs solubilized very high quantities of the poorly water-soluble drugs, danazol and itraconazole, and maintained drug solubilization under simulated gastro-intestinal conditions. A danazol-containing self-emulsifying IL formulation gave rise to 4.3-fold higher exposure than the crystalline drug and prolonged exposure compared with a lipid formulation.