There are several videos and online advices asking people not to allow health care professionals to point the infrared thermometers to your head. The claim is that these thermometers emit infrared rays that can cause brain damage or brain cancer. These advices also suggest asking to point the thermometers to wrists as they are supposedly safe. Several of the people talking in these videos claim to be doctors and neurologists who claim to be experts in the matter.
The claim is FALSE.
Infrared thermometers do not emit infrared radiations, but work by absorbing and measuring them. Primary source of infrared rays in heat. All hot objects emit infrared radiations. Infrared thermometers focus incoming light including infrared rays using a lens onto a detector called thermopile, thereby calculating the temperature.(source)
Another misconception is around the red light or laser that is emitted by certain thermometers. These are not harmful. These are not infrared rays. These are just for ease of use in helping the person to identify where they are pointing at. These are useful when measuring temperature of small area and not necessary while measuring human temperature.(source)