Medically Reviewed by Carol DerSarkissian, MD on September 05, 2021

Types of Thirst


Before pinpointing the reason behind your thirst, It’s important to know whether you’re dealing with excessive thirst (your doctor may call it polydipsia), or dry mouth -- or both. This will help you and your doctor narrow it down.



It’s the feeling that you need to drink lots of fluid. Drinking more doesn’t make the feeling of thirst go away. Dry mouth can also go along with this feeling of extreme thirst.

Dry Mouth


Dry mouth happens when your salivary glands aren’t putting out enough saliva to wet your mouth properly. This can make your mouth, throat, and tongue feel sticky and dry. It can also give you chapped lips and trouble swallowing. Dry mouth can be both a cause and symptom of thirst.



One of the most common causes of excessive thirst is having too much sugar in your blood. When your kidneys get maxed out from filtering sugar from your blood, the glucose overflow goes into your urine, taking fluids from your tissues with it. This makes you pee more, and your body dehydrates, making you thirsty. Thirst is a typical first symptom of diabetes.

Cystic Fibrosis


It can affect not only your respiratory system, but your GI tract, too. It can cause the same symptoms as high blood sugar, like excessive thirst. Other symptoms include constipation, not being able to gain weight, large, oily bowel movements, and poor growth.



When your body doesn’t have enough red blood cells, either because too many are being destroyed or lost, or because not enough are being made, you have anemia. Excessive thirst is a rare symptom of it, along with more common symptoms like shortness of breath, fatigue, feeling dizzy or faint, a rapid pulse, and muscle cramping.

Cushing’s Syndrome


It happens when your body has too much of the hormone cortisol. Feeling thirsty can be a sign of it. You’d likely also have other symptoms like a round face, a fatty hump between your shoulders, purple streaks on your skin, and weight gain.

Sjogren’s Syndrome


Dry mouth is one of the primary symptoms of this autoimmune disease. It’s marked by dryness in the mouth, eyes, and other places in the body. Along with this dry feeling, you’re likely to have joint pain and overall fatigue.



The extra blood that goes through your body when you’re pregnant makes you head to the bathroom more. This can cause dehydration. Your thirst may be a sign you need to bump up the amount of water you drink while sporting your bump. It can also be a sign of gestational diabetes, so check in with your doctor to be sure all’s well with your blood sugar.



Tobacco can affect how much saliva your body makes. This can lead to dry mouth and the feeling of thirst. Smoking can also make your saliva thicker and less wetting for your mouth.



Simply put, you might be thirsty because you’re losing more fluids than you’re taking in. Vomiting, diarrhea, sweating a lot, or not drinking enough water can cause it. Dehydration can also make you dizzy and lightheaded, and turn your pee dark.

Kidney Failure


If you have chronic kidney disease, excessive thirst could be a sign you’re entering end-stage kidney disease. Along with thirst, you’ll also likely feel generally unwell. You could also have itchy, dry skin, as well as a headache, nausea, and a big drop in appetite. You may lose weight, too.

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American Dental Association: “Xerostomia (Dry Mouth).”

Teen Health: “Polydipsia,” “Dehydration.” “Polydipsia.”

Mayo Clinic: “Diabetes symptoms: When diabetes symptoms are a concern,” “First trimester pregnancy: What to expect.”

American Lung Association: “Cystic Fibrosis Symptoms, Causes & Risk Factors.”

National Heart, Lung, and Blood Institute: “Your Guide to Anemia.”

UCLA Health: “Cushings Syndrome.”

Sjogren’s Syndrome Foundation: “About Sjogren’s.”

National Health Service (U.K.): “Gestational Diabetes.”

Journal of Dental Research, Dental Clinics, Dental Prospects: “Effect of Long-term Smoking on Whole-mouth Salivary Flow Rate and Oral Health.”

Acta Stomatologica Croatica: “The Effect of Tobacco Smoking on Salivation.”

Penn Medicine: “End-Stage Kidney Disease.”