Notice whether you get symptoms after consuming milk, ice cream, cheese, or other dairy products
Watch for bloating
Watch for gas
Watch for stomach cramps
Watch for diarrhea
Watch for nausea
See whether symptoms start within a few minutes to a few hours after dairy
Check whether symptoms improve when you avoid lactose
Try a lactose-free diet for a short period and see if symptoms stop
Reintroduce dairy and see if symptoms return
Compare your reaction to milk with your reaction to yogurt or hard cheeses
Consider whether symptoms happen more with larger amounts of dairy
Ask a doctor about a hydrogen breath test
Ask a doctor about a lactose tolerance test
Ask a doctor about ruling out milk allergy or other digestive problems