Notice whether you get symptoms after consuming milk, ice cream, cheese, or other dairy products
Look for bloating
Look for gas
Look for stomach cramps
Look for diarrhea
Look for nausea
Check whether symptoms start within a few minutes to a few hours after dairy
See whether symptoms improve when you avoid lactose
Try a lactose-free diet for a short period and note any changes
Reintroduce dairy and see whether symptoms return
Compare your reaction to lactose-free milk or hard cheeses versus regular milk
Consider whether symptoms are worse after larger amounts of dairy
Ask a doctor about a lactose intolerance breath test
Ask a doctor about a lactose tolerance test
Ask a doctor about stool acidity testing if needed
Rule out other causes such as milk allergy, irritable bowel syndrome, or other digestive problems
Seek medical advice if symptoms are severe, persistent, or involve weight loss, blood in stool, or vomiting