Heartburn vs. Acid Reflux vs. Indigestion
The terms overlap in everyday conversation, but they do not mean exactly the same thing. Knowing the difference can make symptom tracking—and the medicine aisle—less confusing.
Acid reflux is the event; heartburn is a symptom; indigestion is a broader feeling
Acid reflux happens when stomach contents move upward into the esophagus. Heartburn is the burning feeling reflux can cause. Indigestion describes upper-abdominal discomfort—such as fullness, burning, bloating or nausea—and may occur with or without reflux.
The difference at a glance
| Term | What it means | Common clues |
|---|---|---|
| Acid reflux | Stomach contents flow back into the esophagus. | Sour taste, regurgitation, burning, symptoms after meals or when lying down. |
| Heartburn | A burning sensation that is commonly caused by reflux. | Burning behind the breastbone that may rise toward the throat. |
| Indigestion | A collection of upper-digestive symptoms, also called dyspepsia. | Upper-abdominal discomfort, early fullness, uncomfortable fullness after eating, bloating, nausea or belching. |
What is acid reflux?
A ring of muscle between the esophagus and stomach normally helps keep stomach contents where they belong. When contents travel backward, that is reflux. An occasional episode can happen after a large meal, but frequent or troublesome reflux may be gastroesophageal reflux disease, or GERD.
Reflux does not always feel like burning. Some people notice a sour taste, food or fluid coming back up, cough, hoarseness or discomfort when lying down.
What is heartburn?
Heartburn is the familiar burning feeling behind the breastbone. Despite the name, it comes from the esophagus rather than the heart—but chest pain should never be casually assumed to be digestive.
Large meals, certain foods or drinks, bending over and lying down soon after eating can be triggers for some people. Personal patterns are more useful than a universal “never eat” list.
What is indigestion?
Indigestion is broader than heartburn. It usually describes discomfort in the upper abdomen during or after eating: feeling full too soon, remaining uncomfortably full, burning or aching in the upper abdomen, bloating, belching or nausea.
Indigestion and reflux can occur together, but one does not automatically mean the other. Medicines, ulcers and other health conditions can also contribute to indigestion symptoms.
How to choose an OTC option more confidently
- Antacids neutralize existing stomach acid and are generally positioned for short-term symptom relief.
- H2 blockers such as famotidine reduce acid and are labeled for relief or prevention of occasional heartburn.
- OTC proton pump inhibitors such as omeprazole are labeled as a 14-day course for frequent heartburn occurring two or more days a week—not for immediate relief.
- Simethicone addresses gas pressure, bloating and fullness; it does not reduce acid.
Before choosing, check active ingredients, directions, age limits, interaction warnings and how long the label permits use. Do not stack acid reducers unless a healthcare professional recommends it.
Three things to remember
- Reflux describes movement; heartburn describes burning.
- Indigestion covers a wider range of upper-abdominal symptoms.
- The correct OTC category depends on the symptom pattern and label—not the broad phrase “upset stomach.”
Compare acid reducers by strength and Drug Facts
WELMATE famotidine offers single-ingredient options for relief or prevention of occasional heartburn associated with acid indigestion and sour stomach.
WELMATE Acid Reducer
Compare original and maximum strength by dose, directions and daily limits.
Shop famotidine 10 mg → Always read and follow the selected product’s Drug Facts label.Frequently asked questions
Is heartburn the same as acid reflux?
Not exactly. Acid reflux is stomach contents moving into the esophagus. Heartburn is the burning sensation reflux may cause.
Can you have acid reflux without heartburn?
Yes. Reflux may cause regurgitation, a sour taste, cough or hoarseness without the classic burning feeling.
Is indigestion caused by too much acid?
Sometimes acid may contribute, but indigestion has many possible causes. Not every case will respond to an acid reducer.
Does simethicone help heartburn?
Simethicone is an anti-gas ingredient and does not reduce stomach acid. Combination products may contain several ingredients, so check the label.
When should I see a doctor about heartburn or indigestion?
Get medical guidance for frequent, persistent, worsening or unexplained symptoms, difficulty swallowing, vomiting, bleeding, weight loss or other concerning changes. Treat chest pain as urgent.
Sources
- NIDDK: Definition & Facts for GER & GERD
- NIDDK: Definition & Facts for Indigestion
- MedlinePlus: Heartburn
Last reviewed September 2026.
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