Given novel infectious diseases such as COVID-19 and antibiotic resistance new antimicrobial discovery is an important research area. Considering that nature is a vast source of bioactive molecules with antimicrobial activity, the main aim of this book is to present a comprehensive outlook of current research in the field of natural antimicrobials. It discusses the antimicrobial activity of medicinal plants, beehives, and mushrooms with a global coverage of antimicrobial agents from rich forests of Brazil (Amazon), North-Eastern forests of Peru, Argentina, Colombia, India, Bangladesh, Nepal, Middle East, Turkey, Croatia, Greece, Germany and Russia. The book covers the results of the in vitro screening of antimicrobial activities of extracts and isolated compounds from natural origins.