Diarrhea
The gas and water accumulating in the gut irritate the lining of the small intestine – giving rise to contractions in the digestive tract. These continuous contractions cause expelling of the contents of the gut and leads to diarrhea. Diarrhea is one of the most troublesome symptoms of lactose intolerance as cause severe dehydration, lack of energy, and lethargy.
Increased stool frequency, liquidity and volume are attributed as diarrhea and, this symptom most commonly manifests in children than in adults.