Dry mouth but drinking lots of water

Q: Why is my mouth dry even though I drink a lot of water?

Its normal to occasionally have a dry mouth if youre dehydrated or feeling nervous, but a persistently dry mouth can be a sign of an underlying problem. You should see your dentist or GP if you have an unusually dry mouth (known as xerostomia) so they can try to determine the cause.

It's normal to sometimes feel thirsty, but it's not normal to constantly feel thirsty even when you're drinking a lot. See a GP to find out what's causing your excessive thirst.

Table of Contents Show

Why am I always thirsty?
Important: Important
Non-urgent advice: See a GP if you have excessive thirst and:
Dry mouth or excessive thirst?
Untreated dry mouth can damage oral health
Tips for relieving dry mouth
Why is my mouth dry even though I drink a lot of water?
How much water should I drink if I have dry mouth?
Is dry mouth a serious symptom?

Why am I always thirsty?

Most of the time if you're feeling thirsty it's because you need to drink more fluids.

This can happen if you:

sweat a lot after doing exercise
are unwell with sickness and diarrhoea
do not drink enough fluids
drink too much alcohol or caffeine
eat salty or spicy food
have a high temperature
are pregnant

Important: Important

Drink more fluids and avoid alcohol or caffeine to see if it helps.

If you do not, you may be at risk of becoming dehydrated.

Check if you're dehydrated

Symptoms of dehydration in adults and children include:

feeling thirsty
dark yellow and strong-smelling pee
peeing little and less than 4 times a day
feeling dizzy or lightheaded
feeling tired
dry mouth, lips and eyes

Find out more about dehydration

Non-urgent advice: See a GP if you have excessive thirst and:

drinking more fluids for several days has not helped
you frequently need to pee
you're pregnant

The GP will check if your excessive thirst is being caused by something – for example, diabetes, anaemia or medicines you're taking.

The treatment you have will depend on what's causing your excessive thirst.

Dry mouth or excessive thirst?

You may think you're thirsty when you actually have a dry mouth.

If it's a dry mouth, you may have:

a burning sensation or soreness in your mouth
changes in your sense of taste
difficulty speaking, eating or swallowing

Find out more about dry mouth

Page last reviewed: 21 April 2021
Next review due: 21 April 2024

Dry mouth can be incredibly uncomfortable, even if you’ve only experienced it for a short while.

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A number of things can cause this problem, but certain medications, infections, dehydration, as well as cancer treatments are the most common causes, according to family medicine physician Neha Vyas, MD.

Some medications, radiation and chemotherapy can actually damage the salivary glands, leaving you to deal with the result: dry mouth.

Untreated dry mouth can damage oral health

Left untreated, dry mouth, which doctors call xerostomia, can lead to various problems, including:

Halitosis (bad breath).
Cavities.
Yeast infections.
Gingivitis (gum disease).
Improper denture fit.

Over time, you may experience changes in taste, difficulty swallowing, and in some cases, speech changes. You may also notice cracks and cuts on your lips at the corners of your mouth, or you could experience a burning sensation on your tongue.

“Dry mouth usually resolves on its own one to two months after completing chemotherapy, but it can last six months to a year after radiation to the head and neck,” says Dr. Vyas.

Tips for relieving dry mouth

Regardless of the cause of your dry mouth, it’s important to do something about it. Dr. Vyas suggests the following:

Stay hydrated. Drink sips of water throughout the day. Ensure you stay hydrated by drinking at least eight to 12 glasses of water daily, unless your doctor advises against it for some reason. Keep a water bottle handy next to you at all times so you can quickly take a sip (or a few!)
Chew gum or suck on hard candy. Chewing sugarless gum or sucking on sugar-free hard candy helps some people. Make sure it’s sugar-free, though, to avoid calorie and carb overload.
Avoid alcohol, caffeine and acidic juices. This means you should stay away from that daily coffee or latte and juices made from citrus fruits as well as that glass of wine in the evening. Watch out for hidden alcohol, too, since they hide in things like mouthwashes.
Moisten your food. Moisten all dry foods with broth, sauces, milk or melted butter. Since your salivary glands aren’t producing enough saliva, this will make it easier to chew and swallow.
Don’t smoke or use chewing tobacco. In addition to the negative impacts these have on your general health, smoking and chewing tobacco can worsen dry mouth. Quitting smoking is one of the most important things you can do to not only help your dry mouth, but your overall health.
Use a humidifier. Use a humidifier at night, especially in winter, to help moisten the ambient air while you sleep.
Brush your teeth after each meal. Soften your toothbrush in a cup of warm water so it’s gentler on your gums. Make sure to brush after each meal and at bedtime. Use a fluoride rinse to prevent tooth decay if you are undergoing radiation treatments.
Talk to your doctor. Your doctor can tell you about products specifically designed to treat dry mouth. Many of these are available over the counter, such as Biotene® products and Oralbalance® moisturizing gel. There are also prescription medications that act as a saliva substitute and others that stimulate the salivary glands to produce more saliva.

Visit your doctor if these treatments do not relieve your discomfort or if you suspect you may have an infection in the mouth.

Why is my mouth dry even though I drink a lot of water?

It's normal to occasionally have a dry mouth if you're dehydrated or feeling nervous, but a persistently dry mouth can be a sign of an underlying problem. You should see your dentist or GP if you have an unusually dry mouth (known as xerostomia) so they can try to determine the cause.

How much water should I drink if I have dry mouth?

Tips for relieving dry mouth. Stay hydrated. Drink sips of water throughout the day. Ensure you stay hydrated by drinking at least eight to 12 glasses of water daily, unless your doctor advises against it for some reason.

Is dry mouth a serious symptom?

Medical conditions: Dry mouth can be a sign of a more serious condition, such as diabetes, Alzheimer's disease, stroke and Sjogren's syndrome. Sjogren's syndrome (SHOW-grins) is an autoimmune disease that causes the body to attack the glands that produce moisture.