swollen stomach and gas are symptoms that are managed based on whether they are of acute onset of chronic in nature. When accompanied by constipation
, the age also matters. However management always starts with diet modifications with increase intake of vegetables, fibre, drinking much water and fluids and exercise. Avoiding gas producing foods and late meals could also be very helpful. A stool exam and culture to exclude any parasites or bacteria at times is useful. Failure of these measures shall demand a more critical evaluation by the gastroenterologist to exclude Irritable bowel syndrome
, polyps or tumours of the intestines.
If its persistent, consulting a gastroenterologist is my suggestion.
Thanks and best regards,