Tuberculosis is a disease that infects approximately one-third of the world's population. Many individuals have latent tuberculosis, in which they are infected with Mycobacterium tuberculosis, but the bacterium is dormant in the lungs, causing no signs of infection. Latent infection is difficult to treat because the bacteria are not dividing while they exist in this dormant state. Antimicrobial drugs work to kill bacteria when they are actively growing and multiplying; latent tuberculosis cannot, therefore, be treated effectively until the bacteria begin to multiply. A new drug, PA-824, produces nitric oxide (NO) gas when it is metabolized inside the bacterial cell. This gas can kill the bacterium from within, “exploding” it and causing bacterial death even when the bacterium is not multiplying, which may in turn lead to new and effective treatments for latent tuberculosis.