The duration of lactose intolerance symptoms can vary from person to person. That's because individuals produce different amounts of lactase, the enzyme that helps digest lactose. People with lower lactase levels may experience more severe symptoms than those with milder lactase deficiency.

Symptom duration and intensity may also depend on how much lactose-containing foods you ingest. Some people with lactose intolerance find that taking an over-the-counter lactase supplement before consuming lactose-containing products helps reduce symptoms. For these reasons, it can be difficult to predict with certainty how long each person's symptoms will last.

Symptoms of lactose intolerance usually begin 30 minutes to two hours after consuming a dairy product or other food or drink containing lactose. Common symptoms can include bloating, abdominal pain, gas, and diarrhea. Symptoms generally improve once the lactose has passed through the digestive tract and is no longer being broken down by bacteria in the colon.  

Fortunately, lactose intolerance symptoms can usually be managed if lactose is avoided or limited. However, if your symptoms are severe, persist despite avoiding lactose, or continue for several days, contact your healthcare provider. They can help determine whether another digestive condition may be contributing to your symptoms.

Clinically reviewed and updated July 2026.