At your age of 18 I would probably attribute it to dietary influences. Most often consuming lot of sweet and sour food can cause excessive salivation. Even other medications like ayurvedic, allopathic and homeopathic med can cause excessive salivation. Salivation is a natural and if you find it very annoying seek a consultation in person and I would advice you against any online medication. There is no derth of online medications, but to keep you in good health always seek an opnion before you consume such med.

Hi..take Tablet-Robinul 1mg every four hours for two days to reduce salivation. Regards

Hello, Causes of saliva overproduction include excessive starch intake, gastroesophageal reflux disease, pancreatitis, liver disease, serotonin syndrome, oral ulcers, and oral infections. Medications that cancause saliva overproduction include clozapine, pilocarpine, ketamine, and potassium chlorate. If nothing of above is there, then don't worry. It is just habitual of yours. Saliva is meant to swallow not meant to spit out. Next time put some chewing gun to mouth and practice swallowing the juice while chewing.