The distress or stomach-ache after eating is actually classified in two ways:

Distress appearing immediately after eating (postprandial distress): symptoms arise half an hour after a meal, such as abdominal bloating, distension, fullness or pressure.

Intestinal distress: Here symptoms usually start half an hour after eating and continue for several hours depending up on person to person. They may involve the stomach, small or large intestine with additional symptoms such as abdominal pain and cramp and/or anal flatus.

Excess gas in the stomach and intestine is quite distressing and it is due to the disordered intestinal movements which delays the passage of gas through the bowel. Drugs might provide a symptomatic relief in the following ways.

The active ingredients may lower the surface tension of the stomach contents to facilitate the action of digestive juices, which will speed up the digestion and the passage of food contents from the stomach into the intestine.

The active ingredients may speed up stomach emptying by changing the stomach’s acidity or increasing the contractions of smooth muscles of the stomach or by some other mechanisms.

The commonly available preparations, usually is combination, may contain the following ingredients.

Antiflatulents
Carminative Oils
Antacids
Sodium Bicarbonate
Charcoal