Sneezing is one of the initial symptoms of upper respiratory disease in
rats. It is also a very normal reaction to air-borne irritants, dust, the
wrong type of bedding (cedar or pine). I have noticed that many new rats go
through a sneezy stage when they first arrive at a new home.
Many people ask the same question that you are when they first get rats. What you need to do is to be aware of other signs of upper respiratory disease. If your rat is sneezing very often, or showing red, porphyrin stains at the eyes and nose, or sounding congested, or losing weight, or having difficulty breathing-- labored breathing-- see a vet. If you need a suggestion see the following lists that have been recommended by pet rat owners from all over.
Here are some articles on respiratory disease and the RMCA Drug Chart (over the counter cold medications are not the best way to treat respiratory disease). The most important thing with a new pet is too make sure that you are meeting its physical needs--to lessen the chance that it will succumb to disease. The following things are very important. Use a dust-free litter/bedding (no cedar or pine!). Keep the litter clean-- no ammonia build up-- that can damage their lungs. Provide a draft-free setting with temperatures you would be comfortable with, and make sure the air isn't too dry (use a warm air humidifier if necessary). Feed a well balanced diet-- not too much protein-- not too many fatty seeds and treats-- give plenty of water, vegetables, fresh fruit, rat block. Keep the environment interesting-- don't overcrowd it.