The average person produces up to 2 quarts (1.9 liters) of saliva a day. Saliva is about 98 percent water, and it is typically swallowed continually as produced as an involuntary reaction. Too much saliva can be the result of the glands that produce it becoming over active or from an individual swallowing less.
Reduced swallowing can be caused by a number of factors. Medical conditions that typically accompany reduced swallowing include sinusitis
, either temporary or chronic; some allergies; hyperactivity of the salivary glands; and enlargement of the adenoids
. Anything that causes sensitivity in the tongue or mouth also can cause an individual to swallow less often and sense that they have too much saliva.
Please visit your General physician once and get yourself evaluated to rule out the conditions mentioned. Also, if you have developed this as a habit, you need to try and break it as you can see that there is no harm in swallowing your own saliva.
And finally, spitting continuously may or may not be good for your health, but it is definitely bad for the health of others who are around you. So please help yourself get rid of the habit.