Persistent dry mouth (xerostomia) is very common and can be frustrating. Here is what might be causing it.

Dry mouth is rarely a direct sign of cancer, but it can be related in a few important ways.

  • Common causes include:
  • Medications β€” hundreds of medications cause dry mouth, including antihistamines, antidepressants, blood pressure medications, and decongestants. This is the #1 cause
  • Dehydration β€” not drinking enough water
  • Mouth breathing β€” especially at night
  • Sjogren's syndrome β€” an autoimmune condition that affects saliva production
  • Aging β€” saliva production can decrease naturally
  • Diabetes β€” high blood sugar levels can cause dry mouth
  • Radiation therapy β€” if you have had radiation to the head or neck for cancer, this can permanently damage salivary glands
  • When dry mouth IS related to cancer:
  • If you have had radiation therapy for head and neck cancer, dry mouth is a common long-term side effect
  • A tumor in a salivary gland can cause dryness, but usually only on one side
  • Very rarely, mouth breathing from a blocked nasal passage caused by a tumor

What to Look For

  • Usually not serious:
  • Started when you began a new medication
  • Worse in the morning (mouth breathing at night)
  • Improves with drinking water
  • Both sides of the mouth equally dry
  • Worth having checked:
  • Sudden, severe dry mouth with no clear cause
  • Dry mouth on one side only
  • Dry mouth with a lump or swelling in the cheek or under the jaw
  • Difficulty swallowing, speaking, or tasting food
  • Dry eyes as well as dry mouth

When to See a Doctor

  • See a doctor if:
  • Dry mouth is persistent and interferes with eating or speaking
  • You have a lump or swelling in your cheek, jaw, or neck
  • You have dry eyes along with dry mouth
  • You have difficulty swallowing
  • You have not changed medications and have no explanation

Clinical Guidance