Flash chromatography is a rapid separation and purification technique used by organic, medicinal, and natural product chemists to isolate one or more compounds in crude chemical mixtures. Flash chromatography requires only a few items—a solid, inert sorbent, a sturdy, inert column, solvents, and a pump or vacuum source. Though, most chemists use automated flash systems with built-in pumps, gradient making capability, in-line detectors, and fraction collectors, all controlled by relatively simple-to-use software. As with any chromatographic technique, the results obtained are dependent on several factors so in order to insure success goals should be set. Chemists use flash chromatography for one reason—to purify and isolate the compound synthesized. Flash chromatography itself is not an overly difficult technique; however, it is the sample complexity that challenges most chemists. Thin-layer chromatography can be a chemist’s most important tool for purifying crude mixtures.