Flash chromatography is a rapid and efficient liquid chromatography technique employed for preparative-scale purifications. It is a modified version of column chromatography, where the mobile phase moves through the column at an accelerated pace using pressurized air or a vacuum. In vacuum-facilitated flash chromatography, the mobile phase is pulled through the column faster than gravity would allow, while in pressurized flash chromatography, also known as “medium pressure chromatography,” an inert gas like nitrogen is used to push the mobile phase at similar flow rates. Specialized instruments maintain constant air pressure or vacuum to ensure steady mobile phase flow and effective sample separation. Additionally, less expensive flow controllers for pressurized air are available. The ability of flash chromatography to produce high-purity compounds makes it an invaluable tool in the fields of pharmaceuticals, natural product isolation, and organic synthesis.