What causes acid reflux?
Acid reflux (GERD) happens when stomach acid flows back up into the oesophagus because the lower oesophageal sphincter is not working properly. It affects roughly 8-33% of people worldwide.
- Main symptoms: heartburn, sour regurgitation, throat tightness, difficulty swallowing
- Main causes: a weak oesophageal sphincter, hiatal hernia, eating habits, excess weight and stress
- Higher risk: people who are overweight, eat late at night, smoke, or are pregnant
- Treated with lifestyle changes together with acid-reducing medicine — antacids, H2 blockers or PPIs
- Left untreated, it can become chronic and lead to complications such as esophagitis or Barrett's oesophagus
- Severe symptoms such as intense chest pain, difficulty breathing, or vomiting blood need immediate medical care
What is acid reflux?
How to treat acid reflux starts with understanding what causes it: acid reflux, or GERD (Gastroesophageal Reflux Disease), happens when acid from the stomach flows back up into the oesophagus because the lower oesophageal sphincter — the muscle ring at the bottom of the oesophagus — relaxes at the wrong time or has weakened.
Normally this sphincter opens only when you swallow, then closes tightly to keep acid from rising. When it becomes loose or relaxes too often, acid rises and irritates the lining of the oesophagus, causing a burning feeling, tightness in the chest, or a sour taste from regurgitation.
🔢 Facts worth knowing:
- 🌏 Roughly 8-33% of people worldwide experience acid reflux (WHO)
- 🇹🇭 In Thailand it is found in about 7-15% of people who see a doctor for digestive symptoms
- 📈 Rates keep climbing, especially among city dwellers under high stress with irregular eating habits
What causes acid reflux
Acid reflux rarely comes from a single cause — it is usually several factors combined.
A weak lower oesophageal sphincter — the main culprit. When it relaxes too often or does not close fully, acid rises easily.
Hiatal hernia — part of the upper stomach pushes up through the diaphragm, which stops the sphincter working properly.
Eating habits — eating late at night, lying down right after a large meal, very spicy or fatty food, or frequent coffee, soft drinks and alcohol.
Excess weight — abdominal fat presses on the stomach and pushes acid upward.
Stress — ongoing stress increases stomach acid production and weakens the sphincter.
Pregnancy — hormones and the growing womb put pressure on the stomach, making reflux more likely.
Certain medicines — some NSAID painkillers, muscle relaxants and blood pressure medicines can relax the sphincter.
📖 Read more: Want to know which symptoms really point to acid reflux? See Acid reflux symptoms — how to tell if it's really reflux
Common acid reflux symptoms
Acid reflux symptoms fall into two groups: the typical ones most people recognise, and the ones many people never connect to reflux at all.
Typical symptoms:
- Heartburn — a burning sensation, especially after eating or lying down
- Sour regurgitation, or a sour or bitter taste in the mouth
- Tightness in the throat, difficulty swallowing
- Nausea, especially in the morning
Symptoms many people don't realise are linked to reflux:
- Chronic cough, especially at night
- Hoarseness or a frequent sore throat without a cold
- Wheezing that feels like asthma
- Unusually frequent cavities (acid erodes tooth enamel)
- Chest pain that some mistake for a heart problem
Table: Comparing the two groups of acid reflux symptoms
| Typical | Atypical |
|---|---|
| Heartburn | Chronic cough at night |
| Sour or bitter regurgitation | Hoarseness, frequent sore throat |
| Throat tightness, difficulty swallowing | Asthma-like wheezing |
| Nausea after eating | Unusually frequent cavities |
| Upper abdominal fullness | Chest pain that mimics heart disease |
⚠️ If you have severe chest pain, difficulty breathing, or vomit blood, seek medical care immediately.
Who is at risk of acid reflux
It is not just people who eat spicy food — the risk factors are broader than most people think:
- Being overweight or carrying extra weight around the abdomen — abdominal fat raises pressure inside the belly
- Eating late at night regularly — lying down within two to three hours of a meal
- Ongoing stress and poor sleep — the stomach produces more acid
- Smoking — nicotine relaxes the oesophageal sphincter
- Pregnancy — especially the second and third trimesters
- Regular use of certain medicines — such as painkillers or muscle relaxants
How is acid reflux treated
Treatment follows three main approaches, depending on severity:
1. Lifestyle changes — the most important first step, useful at every level of severity.
2. Medicine — if lifestyle changes are not enough, acid-reducing medicines help control symptoms and let the oesophagus heal.
3. Surgery — for severe cases that do not respond to medicine, or when complications develop, a doctor may consider surgery to reinforce the sphincter.
💡 Read more: Wondering how to manage chronic acid reflux long-term? See Chronic acid reflux — how to manage it long-term
Medicines used to treat acid reflux
Acid-reducing medicines come in several classes, each working differently and suited to different levels of symptoms.
Fast-acting antacids — such as aluminium hydroxide or magnesium hydroxide, neutralise acid immediately but wear off quickly, best for occasional symptoms.
H2 blockers — such as famotidine, reduce acid production moderately and last longer than antacids.
PPIs (Proton Pump Inhibitors) — such as Omeprazole or Esomeprazole (Nexium), are the strongest class, cutting acid production by up to 90%, and suit moderate to severe or chronic symptoms.
Table: Comparing the three classes of acid-reducing medicines
| Drug class | Mechanism | Onset | Duration | Best for |
|---|---|---|---|---|
| Antacid | Neutralises acid directly | Very fast (minutes) | 1-3 hours | Occasional symptoms |
| H2 blocker | Partially reduces acid production | 30-60 minutes | 6-12 hours | Mild to moderate symptoms |
| PPI | Blocks the acid pump directly | 1-2 hrs (full effect in 2-3 days) | 24 hours+ | Moderate to severe or chronic symptoms |
📖 Read more: Want a detailed comparison of acid-reducing medicines? See PPI vs antacid — how to choose the right one for you
Lifestyle changes to prevent acid reflux
Medicine alone is not enough — if habits stay the same, acid reflux tends to keep coming back.
Eating habits:
- Eat smaller, more frequent meals instead of eating until overly full
- Avoid acid-triggering foods such as very spicy or fatty dishes, chocolate, coffee, soft drinks and alcohol
- Avoid eating within at least three hours of bedtime
Sleep habits:
- Raise the head of the bed by 6-8 inches (not just stacking pillows higher)
- Sleeping on your left side reduces reflux better than sleeping on your right
Other habits:
- Lose weight if you are overweight
- Quit smoking
- Avoid tight clothing around the waist
- Manage stress and get enough rest
💡 Read more: Want to know what you can eat and what to avoid? See Acid reflux diet — what to eat and what to avoid
Complications to watch for
Leaving chronic acid reflux untreated can lead to serious complications over time.
Table: Complications of acid reflux
| Complication | Caused by | Risk |
|---|---|---|
| Esophagitis (inflammation) | Repeated acid damage to the oesophageal lining | Burning pain, painful swallowing, possible bleeding |
| Esophageal stricture (narrowing) | Scarring from repeated inflammation | Difficulty swallowing, food getting stuck |
| Barrett's oesophagus | Long-term acid exposure changing the lining cells | Higher risk of oesophageal cancer |
| Airway problems | Acid irritating the throat and lungs | Chronic cough, worsened asthma |
| Dental problems | Acid eroding tooth enamel | Cavities, worn enamel, tooth sensitivity |
Frequently Asked Questions
Acid reflux can be well controlled with medicine and lifestyle changes. Many people improve enough to stop taking medicine regularly, but symptoms often return if old habits come back.
Acid reflux happens in the oesophagus, while a stomach ulcer forms in the stomach itself. The symptoms can feel similar, but the location and treatment differ — see a doctor if you are not sure which one you have.
PPIs used continuously for many months to years may affect how the body absorbs calcium and magnesium. Use them as directed and check in with a doctor periodically.
Pregnant women should ask a doctor before using any medicine. Lifestyle changes — smaller meals, raising the head of the bed, and not lying down right after eating — are the safest place to start.
See a doctor promptly if symptoms last more than two weeks, do not improve with medicine, or if you have difficulty swallowing, unexplained weight loss, or vomit blood.
Avoid very spicy or fatty foods, chocolate, coffee, soft drinks and alcohol, and don't eat within three hours of bedtime — these are the most common reflux triggers.
Yes. Acid reflux can trigger a chronic cough (especially at night), hoarseness, a frequent sore throat, or wheezing that feels like asthma, even without the classic heartburn.
Antacids such as aluminium or magnesium hydroxide neutralise acid quickly but wear off fast, best for occasional symptoms. PPIs such as Omeprazole cut acid production by up to 90% and suit moderate to severe or chronic reflux.
⚠️ Disclaimer
The information on this page is for general informational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment from a qualified doctor or pharmacist. If you have any questions about your symptoms or medication, always consult a doctor or pharmacist first.
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