Galenical preparations are medicines prepared according to formulas of Galen that contain mainly herbal or vegetable matter. They are prepared through extraction of active plant principles using solvents like water or alcohol. Common types include infusions, decoctions, tinctures, oils, and extracts. Extraction methods involve comminution, penetration of the plant material by the solvent, dissolution and diffusion of active principles, and separation from insoluble material. Key terms include menstruum (solvent), marc (insoluble plant material), and various extraction techniques like percolation, expression, filtration, and distillation. Common classes of compounds extracted include volatile oils, resins, gums, glucosides, alkaloids