Why do we sneeze?

According to textbooks, the function of a sneeze is to send a strong blast of air through the nose to remove foreign bodies. Three simple tests are described that show that the current views are wrong. The pressure developed in the mouth/pharynx of the author during a sneeze was recorded as about 135 mm Hg reached in about 0.1 s. A forced maximal expiration but with the nose and mouth closed produced a nasal secretion although of smaller amount than in the sneez, in spite of a greater pressure; this is probably because the speed of tension development was much slower than in the sneeze. It is proposed that the high pressure stimulates secretory neurons via branches in the roof of the mouth. The nasal secretion dilutes irritant material in the nose and thus prevents it getting into the lungs.