Primum Non Nocere. In practice, “First do no harm” might be more accurately stated “First do no relative harm.” Medications have side effects and surgeries have complications, but an ethical physician counsels a patient on a course of treatment in which the benefits outweigh the risks. Neurologists who prescribe disease-modifying therapies (DMT) for multiple sclerosis (MS) know this all too well. While DMT can slow disease progression, these medications can produce significant and sometimes dangerous side effects. Here balancing risks and benefits to “do no harm” is not a simple or straightforward task. For this reason, the American Academy of Neurology released guidelines for the use of DMT in MS in 2002, with updates to the guidelines released in April of 2018. They offer significant guidance on starting, switching, and stopping patients, with a heavy emphasis on counseling patients. The guidelines recommend stopping DMT in patients who do not have ongoing relapses (or gado...