Developed as an antibiotic 30 years ago, a drug called minocycline was later discovered to ease acne, rheumatoid arthritis, and other inflammatory conditions. A few years ago, it was shown to slow and even limit the neuronal damage caused by stroke and Huntington’s disease in mice. But researchers were not sure how it works in the brain. In May 2002, a Harvard Medical School research team composed of Shan Zhu, Robert Friedlander, and their colleagues reported that minocycline helps to protect mice from yet another neurodegenerative illness, amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease. The researchers also reported — in the May 2, 2002, issue of Nature — that they have figured out the secret behind minocycline’s neuron-saving powers. This discovery could lead to new approaches to treating ALS and Huntington’s as well as brain trauma and stroke.