Alemtuzumab is effective in relapsing remitting multiple sclerosis (RRMS). Serious adverse events have led to a renewed safety reassessment by the European Medicines Agency (EMA), leading to an approval under strict conditions. We report a RRMS patient experiencing diffuse alveolar hemorrhage (DAH) on day 4 of her first alemtuzumab cycle. In addition, we present an overview of the cases of alemtuzumab-induced DAH that were included in EMA's review procedure, additional well documented cases reported to the EMA and those cases reported in the literature. Combining these cases revealed striking similarities. Importantly, DAH was an early complication. All RRMS patients with known outcome showed complete recovery.