Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

Lactose intolerance

7-minute read

Key facts

  • Lactose intolerance is when you can’t break down lactose.
  • Lactose is the main sugar found in milk and other dairy products.
  • Lactose intolerance happens when your body does not produce enough lactase — the enzyme that breaks down lactose.
  • If you're lactose intolerant, you don't need to stop eating foods with lactose in them altogether.
  • Milk allergy isn’t the same as lactose intolerance.

What is lactose intolerance?

Lactose intolerance is when you can’t break down lactose. Lactose is the main sugar found in milk made by mammals. Lactose can be found in:

  • milk including evaporated milk, milk powder, condensed milk
  • yoghurt
  • ice cream
  • soft cheeses
  • buttermilk
  • other dairy products made from milk

It’s sometimes referred to as dairy intolerance and is rarely serious.

Lactose intolerance is different from milk allergy.

Milk allergy

Milk allergy is an immune reaction to cow’s milk protein.

Milk allergy can be:

  • mild
  • moderate
  • serious

Mild milk allergy can cause:

Severe milk allergy can cause:

Get urgent medical advice if you suspect a serious allergic reaction. A serious allergic reaction is a medical emergency.

Milk allergy isn’t the same as lactose intolerance.

What are the symptoms of lactose intolerance?

The symptoms of lactose intolerance are:

The symptoms usually come on 30 minutes to a few hours after eating or drinking products containing lactose. Drinking just 1 cup of milk can cause symptoms.

Symptoms of lactose intolerance are often dose related — the more you eat the worse they get!

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes lactose intolerance?

Lactose is a natural sugar found in dairy foods. Lactose is normally broken down by an enzyme called lactase. Lactase is made in your small intestine.

Lactose intolerance happens when your body does not produce enough lactase.

Instead, the unabsorbed lactose moves into your large intestine. Here it’s digested by bacteria using their own enzymes. The gases created in this process can produce symptoms.

Most people can break down lactose when they're born. However, it’s normal for there to be less lactase activity as you age.

There are other factors that may also increase your risk of developing lactose intolerance.

Genetic factors

Lactose intolerance is often due to genetic factors. You are more likely to be lactose intolerant if you are:

  • East Asian
  • West African
  • Middle Eastern
  • Southern European — Greek and Italian
  • Aboriginal and Torres Strait Islander

Other causes of lactose intolerance

Lactose intolerance can also be caused by medical issues, such as:

  • gastroenteritis — which strips your intestines of lactase for a week or 2
  • a parasitic infection — which can lower your lactase levels
  • coeliac disease — the lactose intolerance should improve with a gluten free diet
  • Crohn’s disease — especially if you have inflammation or surgery to your small intestine

When should I see my doctor?

If you think you might have lactose intolerance, it’s important to see your doctor.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is lactose intolerance diagnosed?

Lactose intolerance is usually tested for by a lactose challenge. This is where you see what happens when you have a large amount of lactose. For example, drinking a milkshake.

Your doctor may suggest that you trial a lactose-free diet. During this time, you will have to monitor what happens with your symptoms. If your symptoms improve, but return when you reintroduce lactose, then you probably have lactose intolerance.

Other tests are sometimes available in private laboratories and hospital clinics. These include the following.

  • Hydrogen breath test — measures hydrogen in your breath before and after a dose of lactose.
  • Blood glucose test — this is done multiple times after taking a dose of lactose.
  • Lactose intolerance genetic test — looks for 4 genetic variations that control how much lactase you make.
  • Small bowel biopsy — a sample of your bowel wall is taken during an endoscopy (when a camera is passed into your intestines). A biopsy is an invasive test, so it isn’t often used.

However, none of these tests will prove that you are lactose intolerant.

How is lactose intolerance treated?

The main treatment for lactose intolerance is to lower the amount of lactose in your diet. You won’t have to remove all lactose from your diet. The amount of lactose you can tolerate will vary from person to person.

It’s a good idea to visit an accredited practising dietitian. They can help you lower the lactose in your diet and still get enough calcium.

Many dairy foods don’t contain large amounts of lactose and are a good source of calcium.

Lactose intolerance can be temporary. It’s possible to slowly reintroduce milk and other dairy products over time.

If your symptoms don’t improve with a lactose-limited diet, you should speak with your doctor or dietitian.

Lactose intolerance and a low FODMAP diet

If you are lactose intolerant and also suffer from irritable bowel syndrome (IBS), you may follow a low FODMAP diet.

Visit this site to find out more about lactose and dairy products on a low FODMAP diet.

Lactose intolerance and medicines

A few people have such bad lactose intolerance that they must not take certain medicines because they contain lactose. It’s best to speak with your doctor or pharmacist if this is the case for you.

Tips to help manage your lactose intolerance

You may also need to change how you eat dairy foods to lower your chance of symptoms.

Build up your tolerance by starting small and slowly increasing your milk consumption. Most people with lactose intolerance can tolerate ½ cup of milk at a time.

Other things to try:

  • drink milk in small quantities
  • eat lactose-containing foods with other foods
  • choose regular fat milk as it has less lactose than low-fat or skim milk
  • hard cheeses are low in lactose and are usually well tolerated
  • yoghurt is also often well tolerated as it contains bacteria that break down lactose

You can buy enzyme tablets and drops from your pharmacy. Taking these before eating lactose containing foods will help stop your symptoms.

Be careful to check the labels of processed foods such as:

  • biscuits
  • cakes
  • cheese sauce
  • cream soups
  • custards

Look for the terms:

  • ‘milk solids’
  • ‘non-fat milk solids’
  • ‘whey’
  • ‘milk sugar’

However, lactose is only likely to be a problem if these terms are either of the first 2 ingredients listed.

Tips to get enough calcium

It’s important to still eat enough calcium. Most adults need at least 1,000 mg of calcium every day — more if you are older or a pregnant woman.

Soy products with added calcium don’t contain lactose and can replace dairy products.

Other foods that are good sources of calcium are:

  • calcium-fortified foods
  • tinned fish with bones, such as salmon and sardines
  • nuts and seeds
  • broccoli and other leafy green vegetables
  • rhubarb

Complications of lactose intolerance

Eating lactose may cause unpleasant symptoms but it won’t damage your bowel (large intestine). There are no long-term complications of lactose intolerance.

Resources and support

If you suspect you have lactose intolerance, it’s wise to speak to a doctor or dietitian. You can find an Accredited Practising Dietitian on the Dietitians Australia website.

For more information about lactose intolerance you can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a wee

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: March 2023

Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results

Lactose intolerance -

Lactase deficient people do not have enough lactase, the enzyme that helps break down lactose and they suffer from lactose intolerance. The main symptoms of lactose intolerance are bloating and wind. 

Read more on myDr website

Lactose intolerance | Dietitians Australia

What is lactose intolerance? We look at common symptoms, how to manage them, and what foods might trigger discomfort.

Read more on Dietitians Australia website

Lactose intolerance - Better Health Channel

Symptoms of lactose intolerance include bloating, gas, abdominal pain and diarrhoea.

Read more on Better Health Channel website

Milk allergy and lactose intolerance in babies and children

Find out more about lactose intolerance and milk allergies in babies and children, including the causes, symptoms, diagnosis and treatment.

Read more on Pregnancy, Birth & Baby website

5 Signs you may be lactose intolerant -

Lactose intolerance is due to not having enough of the enzyme lactase to digest the sugars, such as lactose, in milk. Find out if you have symptoms or signs.

Read more on myDr website

Food intolerances: children & teenagers | Raising Children Network

Food intolerance symptoms in children and teens include bloating, diarrhoea and stomach pain. If you think your child has food intolerance, talk to your GP.

Read more on website

Food allergy versus food intolerance -

A food allergy is an immune response triggered by eating specific foods that cause certain well known symptoms to develop.

Read more on myDr website

Food and IBS | IBS and your Diet | Symptoms of Food Intolerance

Food and IBS: IBS symptoms and eating habits are closely related. Some foods can trigger a flare up of symptoms and/or make them worse.

Read more on website

Food intolerance - Australasian Society of Clinical Immunology and Allergy (ASCIA)

Around 1 in 20 infants and 1 in 100 adults are allergic to food. Severe reactions result in difficulty breathing, severe rashes, swelling of the face or throat, dizziness, stomach upset or a drop in blood pressure (shock) and loss of consciousness.

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Cow's milk (dairy) allergy | Dietitians Australia

Cow's milk allergy is common in babies and children, and symptoms can range from mild to severe. Avoiding cow's milk and other dairy-containing foods is the only effective way to manage a cow's milk allergy, but it's important to seek specialist advice.

Read more on Dietitians Australia website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Queensland Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.