Your saliva is yours and of course is not going to hurt but help you.
Salivation is usually promoted by chewing (such as gum) or sight, smell, taste, or even thought of food. Very unlikely but it can be induced by a tumor of the salivary gland
but that would be unilateral. If concerned see a dentist or physician for further consult. It won't hurt to just keep swallowing it as well.