What are the Most Common Causes of Dry Mouth and Nausea?

Quite a few different conditions can cause dry mouth and nausea, including various diseases, medications and treatments, and different personal habits. Extreme dehydration tends to be the most common cause of the two occurring together. Both are also documented side effects of chemotherapy, and may also come as a result of certain medical interactions or overdoses. Many women also experience both dry mouth and nausea in the early stages of pregnancy. For most people, simply having both symptoms isn’t concerning in and of itself, particularly if they don’t last long. When the problems seem persistent, though, or seem to be getting worse with time, most medical experts recommend scheduling an appointment in order to find solutions.

The human mouth is usually very wet, and under ideal conditions the lips stay moist and the saliva coats the inner cheeks and tongue. When a person has what’s known as “dry mouth,” he or she often has chapped lips and a sandpaper-like feeling in the mouth, and it’s often more difficult to speak or swallow. The person may also experience bad breath, feel hoarse, or want to drink a lot of water.

Nausea, on the other hand, is a feeling of general queasiness that can cause a person to feel dizzy or seasick. It comes before a person vomits, though people can and often do feel nauseous without actually vomiting. Motion sickness is a common cause, as is any kind of intestinal or stomach upset. Nausea followed by vomiting is one of the main causes of dry mouth, especially if a person becomes dehydrated from vomiting.

Dehydration is one of the biggest causes of the conditions happening together. The human body is made mostly of water, and it needs a regular intake of water and other hydrating fluids in order to maintain proper functioning. When not enough is coming in, places like the mouth often begin drying up in order to shuttle the available moisture to organs like the heart and brain that need it more critically.

Water shortages can also impact the digestive system, and often leads to diarrhea and loose stools. These can cause pain in the abdomen that can lead to stomach upset, queasiness, and nausea.

The most basic reason people develop dehydration is by not drinking enough water, particularly if they are engaging in strenuous activities like running. Skiers and winter sports enthusiasts are often particularly at risk because many don’t actually feel thirsty if they’re also feeling cold, but the body still needs the same amount of water regardless the outside environment. Dehydration is also more likely if a person is sick, since more water is needed in these circumstances to fight the infection — and depending on what that infection is, nausea and dry mouth could be side effects anyway.

People who drink excessively may also experience the two symptoms together. Alcohol dehydrates the body and also puts a strain on the digestive system when it comes to processing and breaking it down. The body can usually process a moderate amount pretty efficiently, but problems tend to arise when internal systems are overwhelmed. People who have consumed too much often develop an intense headache and dry mouth, and frequently also feel as if they’re about to vomit. Vomiting is actually a common outcome in many situations, though in most cases the feelings of nausea persist even after being sick. Smoking and using tobacco products can also cause a person to experience dry mouth, and excessive smoke inhalation can lead to nausea particularly in people who aren’t used to it.

Dry mouth and nausea may also be caused by factors beyond a person's control. Someone going through chemotherapy is likely to experience both, for instance. The chemicals used in chemotherapy to destroy cancerous growths can also damage a person's salivary glands, especially if the person is undergoing treatment for cancer on the neck or head. Nausea is also likely, probably as a result of how very strong the drugs are and how little patients usually want to eat during treatment. If a patient suffers nausea during chemotherapy, his or her doctor may be able to prescribe a medication to prevent it or at least lessen its intensity.

Other medications sometimes cause dry mouth and nausea, particularly when they’re taken in high doses or on an empty stomach. Pain medicines such as ibuprofen, anti-depressants, and antibiotics are some of the most common culprits. Medicine for patients with HIV/AIDS or Parkinson's disease may also lead to dry mouth. A patient who experiences extremely unpleasant dry mouth or nausea may ask his or her healthcare provider to adjust the dose or switch to a different formulation.

Nausea can also occur when a person is in the early stages of pregnancy. Many women experience a condition known as “morning sickness,” which is nausea that is often followed by vomiting. It’s often most common first thing in the morning, but can also strike any time; it usually subsides by the end of the first trimester, but not always. Dehydration is often more of a risk during pregnancy, too, since women need to take in a lot more water than normal; between this and any vomiting, dry mouth isn’t all that uncommon, either. Intense emotions such as fear and excitement can also make a person feel queasy.