The BCG vaccination was an important step towards containing tuberculosis. However, it only helped when the vaccine was given to small children. Adolescents and adults remained unprotected, and millions of them were killed every year by the so-called white plague. An antibiotic had to be found—but how? Where should one look? Louis Pasteur (1822–1895), the great researcher and scholar, paved the way for the discovery of such a remedy. Pasteur had argued that the soil had to be hostile to pathological bacteria; otherwise, it would harbor an ever-growing conglomeration of germs. It soon became apparent that when anthrax, typhoid, staphylococcus, diphtheria, and other bacteria are added to the soil, they are quickly fought off by the soil microbes. Apparently, various microorganisms are capable of producing substances that either inhibit bacterial growth (bacteriostatic) or kill bacteria (bactericidal) or both. The work of Selman Waksman and Albert Schatz in the United States led to the discovery of streptomycin, which was isolated from the bacterium Streptomyces griseus and then successfully used to treat tuberculosis. Another drug was developed in Sweden by Jürgen Lehmann: its name is PAS and is a derivative of the famous substance salicylic acid. The exciting history, the mechanism of action, and the use of these active ingredients in the treatment of tuberculosis are described in more detail in this article.