Digestion (alchemy)

In alchemy, digestion refers to the process by which raw materials are transformed into a more purified or refined state. This concept is akin to the biological process of digestion in living organisms, where food is broken down into simpler forms for nourishment. However, in alchemy, digestion is metaphorical and symbolic rather than biological. The term is often used to describe the maturation of materials, where a substance undergoes a series of stages that lead to its ultimate transformation. This process typically involves heat, moisture, and time, allowing the substance to be 'digested' or broken down into its essence. Alchemy describes several stages of digestion, which are critical to achieving the 'philosopher's stone,' the legendary substance thought to grant immortality and the ability to transmute base metals into gold.

The alchemists believed that artificial metallic transmutation was possible as an analogy to what appeared to be a naturally occurring process of base metals being transformed into more noble ones, as their compositions were slowly altered over a period of thousands of years by the action of subterranean heat and water.