By Angelica Bottaro 

 Medically reviewed by Karina Tolentino, RD

Stomach discomfort can be caused by a variety of health conditions. Some common culprits include indigestion, gastroesophageal reflux disease (GERD), and celiac disease, which is characterized by gluten intolerance. Some medications can also result in stomach discomfort.

Some conditions can cause recurring stomach discomfort. If you experience mild stomach discomfort, it’s important to track your triggers to help your doctor arrive at the correct diagnosis.

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Catherine McQueen / Getty Images 

Indigestion

Indigestion, also called dyspepsia, causes mild stomach discomfort in the upper area of the abdomen. It is not considered a disease but rather a collection of symptoms that starts following a meal.

How Common Is Indigestion?

About 25% of people in the United States experience indigestion each year.1

This condition is mostly brought on by eating too much at once or by eating too quickly. Foods that can increase the risk of indigestion include spicy, greasy, or fatty foods. Other potential causes include:2

• Feeling stressed

• Drinking too much alcohol, coffee, or carbonated beverages

• Eating foods that contain too much acid, such as tomatoes and oranges

• Smoking

• Taking certain medications, such as certain antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs)

The stomach discomfort in indigestion is caused by increased sensitivity of the lining of the digestive system to acidity or stretching. In some cases, stomach acid can break down the lining and cause irritation and inflammation.

Treatment for indigestion typically involves medications and changing problematic eating habits, such as avoiding trigger foods, eating smaller meals more frequently throughout the day, and reducing alcohol and caffeine intake. Antacids may also help.   

GERD

GERD leads to symptoms such as heartburn, chest pain, and stomach pain. It occurs when the muscle at the end of your esophagus, called the lower esophageal sphincter, does not close properly.3 This allows stomach acid and the food you eat to make its way back up the esophagus, which connects your throat to your stomach.

Factors that may affect the lower esophageal sphincter and lead to GERD include:4

• Being overweight or having obesity

• Being pregnant

• Smoking or inhaling secondhand smoke

Treatment for GERD typically includes lifestyle changes. This includes losing weight, avoiding trigger foods, and eating smaller meals. Keeping your head elevated when you lie down and avoiding lying down after you eat can also help.

Medications can help with symptoms, including antacids and medications like H2 blockers and proton pump inhibitors that reduce the amount of acid your stomach makes.5 Antacids are available over the counter (OTC), while H2 blockers and proton pump inhibitors are available both OTC and as prescriptions.

Lactose Intolerance

Lactose intolerance occurs because the small intestines lack enough of the digestive enzyme lactase to help break down and digest milk sugars, which are known as lactose.

When your body doesn’t have enough lactase, the lactose in food makes its way into the colon, the large intestine, where bacteria begin to ferment and break it down. This is what causes stomach discomfort and other symptoms like bloating and gas.6

The main treatment for lactose intolerance is to avoid dairy products such as milk and milk products. Some people may only need to limit the amount of lactose they eat or drink, while others may need to avoid lactose altogether. 

Beware of Hidden Dairy in Packaged Foods

Lactose can hide in foods such as butter, baked goods, cereals, and processed foods that are battered, like chicken wings and chicken fingers.

You can also take lactase tablets before you eat or drink milk products or add lactase drops to milk before you drink it. The lactase breaks down the lactose in foods and drinks, reducing your chances of having lactose intolerance symptoms. However, young children and pregnant people may not be able to use lactase products. Check with your doctor before trying them.7

Medication Side Effects

Some oral medications can irritate various parts of the gastrointestinal tract and cause stomach discomfort. If medications get stuck in the esophagus or don’t make their way to the stomach, they may release chemicals and cause irritation. Some medications can hinder the way the lower esophageal sphincter muscle operates.8

A common class of medications associated with stomach discomfort is NSAIDs. This includes medicines such as ibuprofen and other common pain relievers. These medicines weaken the ability of the lining to resist acid made in the stomach, and can sometimes lead to inflammation of the stomach lining (gastritis), ulcers, bleeding, or even perforation of the lining.8

People with a food intolerance, such as gluten intolerance, must be sure medicines do not contain fillers or additives with these substances.8

With some medications, the stomach discomfort will ease once the body gets used to it. With others, if the discomfort is too much to deal with, doctors will typically suggest trying a new medication or taking OTC medications that can help ease symptoms.

To prevent these medications from irritating your stomach:8

• Take coated tablets.

• Do not drink alcoholic beverages when taking these medicines.

• Take medicines with food or a full glass of milk or water.

Gluten Intolerance

Gluten intolerance occurs when your body cannot digest or break down gluten. Gluten is a protein that can be found in wheat, barley, rye, and other grains.

Studies have shown that gluten intolerance stems from a weak intestinal barrier. When someone with a weak barrier consumes gluten, an inflammatory immune response is triggered, which leads to symptoms such as bloating, pain, cramping, headaches, and fatigue.9

There is a serious form of gluten intolerance called celiac disease. It is an autoimmune disease in which eating gluten leads to inflammation and damage to the small intestine over time.

Treatment for gluten intolerance and celiac disease usually involves avoiding foods with gluten and eating a gluten-free diet.

Thyroid Disorders

The thyroid is a gland that produces hormones to help the body function. When the thyroid doesn’t work as it should, a thyroid disorder occurs.

It can become overactive or underactive. Hypothyroidism is when your thyroid doesn’t create enough hormones, and hyperthyroidism occurs when your thyroid makes too much of one specific hormone known as thyroxine.

There are many different types of thyroid disorder, including:10

• Thyroiditis, which is inflammation of the thyroid gland

• Hashimoto’s disease, an autoimmune disease in which your body attacks the thyroid gland

• Graves' disease, an autoimmune disorder that causes an overproduction of thyroid hormone

• Nodules

• Excessive iodine or deficiency in iodine

Research has shown that thyroid disorders and gastrointestinal issues often go hand in hand.11

To treat the stomach issues caused by thyroid disorders, the disorder that's causing it needs to be treated. In the event that thyroid disorder medication is causing stomach issues, other forms of treatment may be explored.

When to See a Doctor

Stomach pain can sometimes be an emergency. To determine if you need to seek immediate medical attention, take note of your symptoms and monitor them. If the pain becomes severe, you notice any bruising, you are pregnant, or you have recently had surgery, you should see your doctor right away.

Frequently Asked Questions

Why do I get an upset stomach after eating?

Certain foods can trigger an upset stomach, such as fatty or greasy foods, dairy products, or foods that contain gluten. If you are not sure what is causing your upset stomach, talk to your doctor about an elimination diet to figure out what food is triggering it.

How do I know if my stomach pain is serious?

Stomach pain is usually harmless, but it can be a sign of a serious health problem. If the pain persists for longer than a few days, worsens over time, or is severe, you should seek medical attention immediately. Conditions such as appendicitis present with stomach pain and can be life-threatening if untreated.

What can I take to get rid of stomach discomfort? 

The cause of your stomach discomfort will determine what you can take to ease it. In the case of indigestion, an OTC antacid is typically used. Prior to self-treating, you should see a doctor for a proper diagnosis.

Why does my stomach bother me when I lie down?

Stomach discomfort can often occur if you lie down too soon after eating. To prevent this, you can eat smaller meals and avoid lying down for at least two hours after a meal.

Summary

Stomach discomfort has many different causes, including indigestion, GERD, gluten intolerance, lactose intolerance, and thyroid disorder. Some medications like NSAIDs can also result in an uncomfortable feeling in your stomach. The best way to treat this discomfort is to identify and treat the underlying cause.

 Sources

Cleveland Clinic. Indigestion (dyspepsia).

National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of indigestion.

Saha L. Irritable bowel syndrome: pathogenesis, diagnosis, treatment, and evidence-based medicine. World J Gastroenterol. 2014 Jun 14;20(22):6759-6773. doi:10.3748/wjg.v20.i22.6759

National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of GER & GERD. Updated July 2020.

Johns Hopkins Medicine. Gastroesophageal Reflux Disease (GERD) Treatment.

Deng Y, Misselwitz B, Dai N, Fox M. Lactose Intolerance in Adults: Biological Mechanism and Dietary Management. Nutrients. 2015 Sep 18;7(9):8020-8035. doi:10.3390/nu7095380

National Institute of Diabetes and Digestive and Kidney Diseases. Treatment for lactose intolerance.

Johns Hopkins Medicine. Medications and the digestive system.

Uhde M, Ajamian M, Caio G, De Giorgio R, Indart A, Green PH, Verna EC, Volta U, Alaedini A. Intestinal cell damage and systemic immune activation in individuals reporting sensitivity to wheat in the absence of coeliac disease. Gut. 2016 Dec;65(12):1930-1937. doi:10.1136/gutjnl-2016-311964

Cleveland Clinic. Thyroid Disease.

Kyriacou A, McLaughlin J, Syed AA. Thyroid disorders and gastrointestinal and liver dysfunction: A state of the art review. Eur J Intern Med. 2015 Oct;26(8):563-71. doi:10.1016/j.ejim.2015.07.017

By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.