You might be reading this while nursing a fever, diarrhoea, and nausea. Perhaps your doctor diagnosed you with stomach flu, and you’re curious to find out what you can do to ease the symptoms. 

We’ve got you covered with some tips to keep yourself hydrated and comfortable during this recovery period. But first, let’s understand what stomach flu is.

What is stomach flu (gastroenteritis)? 

"Stomach flu or food poisoning (known medically as gastroenteritis) is a contagious foodborne illness (spread through food). Most cases of acute diarrhoea in adults are due to viral infections and are self-limited. It usually happens after eating contaminated food, drinking contaminated water, or having close contact with an infected person. 

For example, you might have eaten some food or drink with stomach flu-causing bacteria or virus in it, or you may have gotten the bacteria or virus from touching another person’s hand or personal belongings," explained Dr Gwendoline Tan, Associate Consultant from Outram Community Hospital (OCH), managed under SingHealth Community Hospitals (SCH). SCH is a member of the SingHealth group.

Even a small amount of contamination can cause stomach flu!

How to manage stomach flu (gastroenteritis)

How to cure stomach flu? There’s no one type of medicine that can ‘cure’ stomach flu because it gets better on its own. That’s right – most cases of stomach flu are self-limiting, meaning that it goes away eventually without medication.

Stomach flu treatments are more to help you feel better, and they include drinking lots of clear fluids, eating soft food and maintaining good hygiene.

Hydration is important!

Stomach flu symptoms like frequent vomiting and diarrhoea can lead to dehydration, because your body loses lots of water each time you throw up or have watery poo.

Prevent dehydration and drink plenty of water to replace lost fluids and electrolytes.

a) Drink enough water

Drink around eight to ten glasses of clear liquid daily (including water and non-oily clear soup). If you feel nauseous, don’t take all this water at one go - sip it slowly throughout the day and don’t force yourself to drink.

After having diarrhoea, drink at least one cup of water to stay hydrated. You can also take some rehydration salts (buy from the pharmacy or get it from your doctor). 

How do you know when you’re drinking enough water?

Your urine should be clear, and your tongue should be wet. 

b) Try home remedies for stomach flu rehydration

Drink boiled barley or rice water with a sprinkle of salt. Barley and rice makes your gut take in more water, helping with stomach flu treatment for water loss. 

c) Don’t drink alcohol and caffeine

If you’re feeling less nauseous, you might be tempted to have some alcohol or coffee to quench your thirst. Sure, these are drinks that contain water and they should be helpful for rehydration. But they’re not.

Don’t drink alcoholic and caffeinated drinks (coffee, bubble tea, some types of packaged tea) when you have stomach flu. Alcohol and caffeine are diuretics that make you urinate more, worsening dehydration.

d) Take an oral rehydration solution

Vomiting and diarrhoea cause your body to lose essential electrolytes like sodium, potassium and calcium. But your body needs these electrolytes to perform daily functions. Rehydration is the most important part of treatment in stomach flu.

Oral rehydration salts like Rehidrat and Dioralyte help replace lost electrolytes and minerals. You can usually find oral rehydration salts in pharmacies (or your doctor might prescribe them). They come in different flavours and different forms: lemon, orange, apple, and blackcurrant-flavoured salts in packets or tablets. 

You’ll usually need to dissolve the tablet or packets in a cup of water and drink it slowly. Follow the instructions on the packaging.

e) Drink fruit, glucose, or de-fizzed drinks

Diluted fruit juices and flavoured soft drinks along with saltine crackers and soups may meet the fluid and salt needs in patients with mild illness. Isotonic sports drinks are not equivalent to oral rehydration solutions, although they may be sufficient for the otherwise healthy patient who is not severely dehydrated.

f) Look out for signs of dehydration

Signs of dehydration from stomach flu include drowsiness, any unusual sleepiness, light-headedness (feeling like your head is floating) and dark urine. 

If you are dehydrated and still cannot swallow liquids, see a doctor immediately.

Stomach flu (gastroenteritis): What to eat and avoid

a) Easy-to-digest food 

The benefit of specific dietary recommendations other than oral hydration has not been well established. However, adequate nutrition during an episode of stomach flu is important. You can try boiled starches such as: 

Porridge or congee

Boiled noodles

Rice

Boiled oats

Boiled vegetables

Plain cream crackers 

Bananas

Soup

Boiled or mashed plain potatoes

If you still have nausea and vomiting, and cannot tolerate food, you can try a liquid-only diet initially.

b) Avoid full-fat dairy products

Dairy products like milk, ice cream and cream-based soup can irritate the gut. This is due to secondary lactose malabsorption, which is common following infection and may last for several weeks to months. 

Thus, temporary avoidance of lactose-containing foods is reasonable.

c) Avoid high-fat food

High-fibre, oily and fatty food is harder to digest. You should rest your digestive system and bowels while recovering from stomach flu, so these foods are a no-no: 

Fried chicken

Popiah

Rojak

Curry

Glutinous rice

French fries

d) Don’t share food or utensils

Stomach flu (gastroenteritis) medicine

Stomach flu medication includes oral rehydration solutions, anti-vomiting and anti-diarrhoea drugs. In certain cases, a course of antibiotics may be required.

a) Anti-vomiting and anti-diarrhoea drugs

You can take anti-vomiting and anti-diarrhoea medications like pepto-bismol and imodium, to reduce nausea and diarrhoea. Don’t take them if you have a high fever or bloody stools, as these mean that you have severe inflammation. 

If your diarrhoea and fever don’t go away after a few days of taking prescribed medication, see your doctor again. 

b) Antibiotics

Your doctor usually won’t recommend antibiotics, as stomach flu goes away by itself without medication.

If you have high fever ≥38.5°C and severe stomach flu symptoms (bloody diarrhoea, more than 6 liquid stools per 24 hours, severe stomach pain), or you are at high risk of severe illness (pregnant, immunocompromised, elderly), your doctor may give you antibiotics to treat stomach flu because it could be caused by a bacterial infection. 

Take your full course of antibiotics as instructed, and don’t reduce or increase the dose without asking your doctor first.

Stomach flu (gastroenteritis): When to see a doctor

How long does stomach flu last? 

The good news is that most stomach flu cases heal quite quickly. Stomach flu usually resolves within 24 hours to two days. 

However, more severe infections take longer to fully recover. See a doctor if you have: 

  • Bloody stools

  • Mucus in stools or vomit

  • Diarrhoea and vomiting get worse and does not stop

  • Severe abdominal pain

  • Fever that lasts more than 3 days

  • Fever that is higher than 39°C

  • Urinating less

  • Feeling faint when you stand up

Stomach flu (gastroenteritis): How to avoid spreading it

Stomach flu can easily spread through eating contaminated food and touching contaminated surfaces. So if you have stomach flu, it is important to:

a) Wash your hands with soap and water 

When should you wash your hands?

  • Before and after eating

  • After using the toilet

  • Before touching common items 

  • Before having physical contact with others (handshake, holding hands, etc.)

b) Avoid close contact with others

After a stomach flu diagnosis, avoid close contact with others to prevent spreading the infection to them. While you’re at home, get plenty of rest and sleep.

c) Clean contaminated surfaces

Clean all surfaces and areas that have been stained with poo or vomit (toilet, sink, shower area) using a bleach-based cleaning solution (you can find one from the supermarket). 

Leave the bleach disinfectant on the contaminated surfaces for at least 5 minutes before washing again with regular soap.

d) Wash contaminated clothing and bedsheets

Your clothes, towels and bedsheets might get stained with vomit or poo, especially if you go straight to bed after vomiting or using the toilet. 

Try not to wash your laundry in the same batch as other people at home. 

Use bleach-based laundry detergent to wash your dirty clothes and bedsheets. Wash them with hot water (kills bacteria) and the maximum machine cycle length (or the longest cycle length on your washing machine). 

e) Wash hands with soap and water

Hand sanitisers don’t always kill norovirus (or other viruses that cause stomach flu). It’s always better to wash your hands with soap and water. 

f) Avoid contact with vulnerable people

Stay away from vulnerable groups like pregnant people, children and older adults, as they have weakened immune systems. They have a greater risk of getting stomach flu from you.

g) Avoid sharing food, utensils and items

Don’t share any dishes, eating utensils and towels. If you must share food, use a serving spoon if you’re sharing a common dish with other people at home.

For more tips on how to avoid getting stomach flu, check out our article on stomach flu prevention here.

Stomach flu (gastroenteritis) symptoms

Common stomach flu symptoms are stomach pain, vomiting and diarrhoea, usually within 8 to 24 hours after ingestion of the contaminated foods. 

Fever may or may not be present. Diarrhoea can range from very mild, self limiting disease of one to a few loose stools and only minimal symptoms, to soft, watery stools that may contain blood, mucus and pus.

Stomach flu is a common illness that happens when you eat contaminated food.  Rest well and stay hydrated for a faster recovery.

Ref: H24

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Good Gut Health: 4 Ways to Protect Your Digestive System

Gastric Pain: Common Causes, How to Prevent and Treat

10 Easy Ways to a Healthier Liver

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