Most normal birds will sneeze occasionally to clear dust or debris from their nostrils. You may even notice a little bit of clear fluid coming from the nostrils just after sneezing. If, however, a discharge continues after sneezing, sneezing is persistent or other signs such as swollen eyes, lethargy or loss of appetite occur, medical attention is needed. To reduce the risk of excessive sneezing, keep your bird in a dust and smoke free area.
For more information, please read the article Sneezing and Nasal Discharge.