ALTE (apparent life-threatening event) and BRUE (brief, resolved, unexplained event) are not specific disorders but terms for a group of alarming symptoms that can occur in infants. They involve the sudden appearance of respiratory symptoms (eg, apnea), change in color or muscle tone, and/or altered responsiveness. The caregiver may fear that the child is dead or that his or her life is in jeopardy. Events typically occur in children < 1 year with peak incidence at 10 to 12 weeks. Some of these events are unexplained (and designated BRUEs), but others result from numerous possible causes including digestive, neurologic, respiratory, infectious, cardiac, metabolic, or traumatic (eg, resulting from abuse) disorders. Treatment is aimed at specific causes when identified.