Notice whether you get symptoms after consuming milk, ice cream, cheese, or other dairy
Watch for bloating
Watch for gas
Watch for stomach cramps
Watch for diarrhea
Watch for nausea
Check whether symptoms start within 30 minutes to 2 hours after dairy
Try avoiding lactose for 1 to 2 weeks and see if symptoms improve
Try reintroducing dairy and see if symptoms return
Compare symptoms after lactose-free milk versus regular milk
Keep a food and symptom diary
Ask a doctor about a lactose intolerance test
Ask a doctor about a hydrogen breath test
Ask a doctor about a lactose tolerance test
Ask a doctor about a stool acidity test
Seek medical advice if symptoms are severe, persistent, or unclear