Yes.  

Doctors often recommend humidifiers in the winter because if your nose and throat get too dry, that raises the risk of getting a cold.
 
But humidifiers can be a breeding ground for mold and bacteria. So the trick is to select the right kind of humidifier and to monitor humidity with a hygrometer to make sure it does not go above about 35 percent, said Jeffrey C. May, a chemist-turned-building investigator who is also the author of  “The Mold Survival Guide.”
 
There are four basic kinds of humidifiers. One simply boils water and pumps it out as hot steam. This can be great for adults because “the heat kills bacteria, mold, viruses – you name it. They’re dead,” said Dr. John Ouellette, a retired allergist from Madison, WI who collaborates with May. The downside is that hot steam products can put too much moisture into the air, and children can scald themselves if they knock the device over or get too close.
 
Another device mixes air with hot steam, so the mist is less humid but still warm, said May. This type, too, kills mold and bacteria, but there is still some scalding risk.
 
Two types of humidifiers pump out cooler mist. One is an evaporative humidifier, which blows air over a paper filter soaked in water. The advantage here is that there is no hot water, hence no scalding danger. But the filter can get dirty and covered with mold.
 
The other choice is an ultrasonic mister, which produces mist by a rapidly-vibrating metal plate that sits under the water in a container. The advantage of this is that there is no scalding danger. The downside is that the droplets in the mist contain minerals that can coat surfaces in the room with fine, white dust.
 
It’s crucial to wash all humidifiers as instructions say, with vinegar or, if you get the evaporative kind, with the chemical tablets that come with it, to prevent microbial growth in the water.  If you don’t clean your humidifier as the instructions recommend, “you’re blowing stuff into the environment that is not good,” said Ouellette.