The document discusses various extraction methods used to isolate active constituents from plants. It describes extraction as removing active components from a solid or liquid using a solvent. Common extraction methods include maceration, percolation, digestion, decoction, and infusion. Maceration involves placing plant material in a solvent for 3-7 days with agitation. Percolation is continuous downward displacement of solvent through packed plant material. Proper extraction requires considering factors like the plant material, solvent, temperature, and particle size. Modern techniques like supercritical fluid extraction are also used.