For one that suffers from acid reflux for a lifetime, it can contribute to some serious conditions. Acid comes up in the esophagus, scars and burns the walls. Food continues down this path, irritating the ulcerated surface, affecting the movement of esophageal contractions; this all adds to the problem.

Infants and children who have Acid reflux may not vomit, but may still have stomach contents that move up the food pipe and spill over into the windpipe and affect the lungs. Asthma, pneumonia, and even SIDS (sudden infant death syndrome) can happen. Infants and children with reflux who vomit frequently may display unsatisfactory growth.

Stomach fluids that reflux into the esophagus damage the cells lining the esophagus. The body typically then reacts with inflammation and this is called Erosive Esophagitis. .

Ulcers and the additional associated inflammation gives rise to bleeding into the esophagus. Sometimes, the bleeding can be severe and may cause severe anemia and require transfusions of blood and endoscopic or surgical treatments.

Because of the scar tissue and ulceration, there is a narrowing of the food pipe. This prevents the easy passage of food, makes swallowing difficult, and can also cause breathing problems- like shortness of breath and wheezing.

After being subjected to gastric acid reflux for such a long time, the cells in the lining of the esophageal wall can change. The cells in the walls can become pre-cancerous, then later cancerous. This condition (Barrett's esophagus) occurs in roughly 10% of all acid reflux patients. There are more and more people being diagnosed with Barrett's esophagus today.

Finally, there are a bunch of nerves in the lower part of the Esophagus, which get disturbed by the Acid Reflux flushing back. This sometimes result in a pain we call heartburn; other times, these nerves transmit the disturbance to some other nerves, that cause constriction of the lung airways, and cough, causing the patient to get breathless.