Sneezing can indicate an infection, an allergy, a foreign body in the nose, or (rarely, and usually only found in older dogs) a nasal polyp or tumor.
Generally, a few discrete sneezing incidents are not a cause for worry. But when in doubt, my first course of action is alway to call my vet. Usually he can tell me over the phone if there is any cause for concern, or not.
Some things to observe:
Is your dog sneezing out of one nostril, or both?
Is there a discharge, and if so, what kind - clear, bloody, mucoid?
(Sneezing caused by allergies tends to be bilateral - you often see a clear discharge from both nostrils. Infections can affect one or both nostrils, and you often see a bloody or mucoid discharge.)
How often does a sneezing attack occur?
How long does an attack last?
When did the sneezing start, and for how many days/weeks has this been going on?
Does your dog paw at his face just before or during an attack?
Are there any other symptoms, such as coughing, wheezing, etc?
Any seasonal connection should be considered, as should the addition of any new substance in the house (cleaning products, a new carpet, perhaps a new houseplant, etc.)
And, just to be check - is this regular sneezing (air being expelled out) or reverse sneezing (air taken in)?
I'd counsel against giving any OTC meds without first speaking to your vet.
A couple of overview articles:
http://www.peteducation.com/article....2+2096&aid=479 http://www.petplace.com/dogs/sneezin...ogs/page1.aspx
Hope your doglet is simply having a one-off reaction to something simple, and stops soon. But do call the vet if worried, and certainly if it persists.