Biotransformation is the process by which living organisms, particularly microorganisms and enzymes, convert substances into different chemical forms. This transformation often occurs in the body to help eliminate toxins, drugs, or other foreign compounds. It can make these substances more water-soluble, facilitating their excretion through urine or bile. In humans, biotransformation primarily takes place in the liver, where enzymes modify drugs and environmental chemicals. This process can either activate a substance, making it more effective, or deactivate it, reducing its potential effects. Understanding biotransformation is crucial in fields like pharmacology and toxicology.