Question: What causes dry mouth? I often suffer from this problem even though I am in otherwise pretty good health.

Dr. Hibberd's answer:
Dry mouth can result in reduced or no saliva, and lead to problems because saliva helps prevent tooth decay by limiting bacterial growth and washing away food particles. Saliva also enhances your ability to taste and makes it easier to swallow. In addition, enzymes in saliva aid in digestion.
Dry mouth is often a side effect of medication, aging, nerve damage, and a host of health conditions. In your case, as you say, you seem to be in good health, you can follow the following tips that will help you from this recurring problem. You could chew sugar-free gum or suck on sugar-free hard candies, limit your caffeine intake, avoid sugary or acidic foods, brush with a fluoride toothpaste, use a fluoride rinse or brush-on fluoride gel before bedtime, avoid mouthwash that contains alcohol, stop all tobacco use, sip water or suck ice chips throughout the day to moisten your mouth and drink water during meals to aid chewing and swallowing.
You may want to look out for over-the-counter saliva substitutes that are available. Try the ones containing carboxymethylcellulose or hydroxyethyl cellulose, such as Biotene Oral Balance. Avoid using over-the-counter antihistamines and decongestants because they can make your symptoms worse. In addition, make it a habit to breathe through your nose, not your mouth, and try to add moisture to the air at night with a room humidifier. However, a final word of advice. It is best to pay a visit to your family physician who will examine if you have any underlying health condition leading to your recurring condition of dry mouth.