Your body has its own built in immune system to protect you from outside elements such as dust, pollen, pollution, etc. If your immune system is not working properly you may suffer from watery eyes, a running nose, sneezing, or many other threats of sicknesses.
Histamines cause most sinus and allergy problems. Most people treat these problems with anti-histamines. These medications will dry the membranes and suppress the symptoms but they are not a cure. Stress can often be a factor when your immune system is not working properly, and when stress is ignored your body cannot correct itself.
The nervous system and immune system, when working properly, can work as a natural healing aid and help to correct your sinus and allergy symptoms.