Heartburn is a pain behind the breastbone which radiates upwards into the throat. This burning pain is caused because of digestive juices, including hydrochloric acid, spilling into the throat from the stomach and irritating the unprotected lining of the esophagus. This happens because of the slackening or relaxing of the Lower Esophageal Sphincter (LES) muscle, which normally acts as a one-way valve preventing the flow of food or digestive juices into the throat. The two main conditions due to which heartburn may occur are gastro esophageal reflux disease and hiatal hernia.

Indigestion is any condition affecting the digestive system and, thereby, the digestive process. Some of the effects of indigestion may be belching, flatulence, bloating, upset stomach, abdominal pain, nausea and occasional vomiting. There is a condition called lactose intolerance, wherein the stomach is not able to digest milk and its products. In certain cases the stomach has a condition called low acidity, which again affects the digestive process. Low motility of the digestive muscles makes the movement of food material in the digestive tract slow, and so the digestive process is affected.

The use of antacids to cure heartburn neutralizes the acid in the throat and the stomach. It reduces the effect of heartburn. But it also reduces the effect of the acids, and so the digestive process itself is affected. If the stomach muscle is also weak, the food is not well-mixed with the stomach juices, and this itself can cause indigestion. Many persons with heartburn also suffer from indigestion. Both problems can exist because of weak muscles in the digestive tract. Whichever way the indigestion is caused, it is important that when heartburn medication is taken, a strict diet is necessary. Avoiding the intake of alcohol and stopping smoking will help to control both indigestion and heartburn. Also, avoiding foods like citrus fruits, spicy foods and fatty foods, and eating bland and simple-to-digest foods is good for both problems.