Fungal metabolites are organic compounds produced by fungi during their growth and development. These metabolites can be classified into primary metabolites, which are essential for the fungus's growth, and secondary metabolites, which often play a role in defense against predators or competition. Secondary metabolites include a variety of substances such as antibiotics, toxins, and pigments. Many fungal metabolites have significant applications in medicine and industry. For example, the antibiotic penicillin, derived from the fungus Penicillium, has revolutionized the treatment of bacterial infections. Other metabolites are used in food production, such as citric acid, which is produced by certain fungi and widely used as a preservative and flavoring agent.