When flying in 2026, the best and safest place to put your electric toothbrush is in your carry-on luggage. The reason for this is that almost all modern electric toothbrushes (such as those from Oral-B or Sonicare) are powered by Lithium-Ion batteries. International aviation safety regulations generally require devices with lithium batteries to be kept in the cabin rather than the cargo hold; in the extremely rare event of a battery fire (thermal runaway), the crew can quickly extinguish it in the cabin, whereas a fire in the cargo hold is much harder to manage. While the TSA and most airlines do technically allow electric toothbrushes in checked bags because their batteries are relatively small and "contained," keeping it in your carry-on ensures it won't be lost if your suitcase is delayed, and it allows you to freshen up during long layovers. To prevent it from accidentally turning on and vibrating in your bag—which can cause a security scare—many travelers suggest removing the brush head and storing it in a dedicated travel case or a small sealable pouch.