Diarrhea is one of the most common health complaints in Canada. It happens when your bowel movements become loose, watery, or more frequent than usual. In this article, we cover the causes of diarrhea, the difference between acute and chronic diarrhea, how to treat it at home, and when it is time to visit your family doctor or a walk-in clinic.
What Is Diarrhea?
Diarrhea means passing loose or watery stools three or more times in a single day. It can be a short-term problem lasting just a day or two, or it can go on for weeks. The condition can affect anyone — from newborns to older adults.
Along with loose stools, diarrhea often comes with other symptoms. These can include stomach cramps, nausea, vomiting, and sometimes fever. In more serious cases, you may notice blood or mucus in your stool.
Most cases of diarrhea are not dangerous for healthy adults. However, it can become a serious concern for babies, young children, elderly people, and anyone with a weakened immune system.
Common Causes of Diarrhea
There are many reasons why diarrhea can develop. Understanding the cause helps guide the right treatment. The causes are generally grouped into short-term (acute) and long-term (chronic) triggers.
Short-Term Causes
Short-term diarrhea is most often caused by an infection. Bacteria, viruses, and parasites are the usual culprits. You can pick these up by drinking contaminated water or eating spoiled food.
Food poisoning is a well-known example. It can affect several people at once if they all eat the same contaminated food. This type of infection spreads through the oral-fecal route — meaning germs pass from stool to mouth, often through unwashed hands.
Other short-term causes include:
Stress and anxiety
Certain medications, including antibiotics
Food allergies or intolerances
Eating too much greasy or rich food
Gastritis (inflammation of the stomach lining)
Long-Term Causes
Chronic diarrhea lasts more than three weeks. It usually points to an underlying health condition. Common causes include inflammatory bowel disease (IBD), such as Crohn’s disease or ulcerative colitis.
Other long-term causes include:
Celiac disease (gluten intolerance), where the small intestine reacts to gluten in food
Irritable bowel syndrome (IBS)
An overactive thyroid (hyperthyroidism), which speeds up digestion
Certain kidney and intestinal disorders
Secretory diarrhea, where the intestinal lining produces too much fluid
Tumours or growths along the intestinal wall
If your diarrhea keeps coming back or does not go away, always speak with a healthcare provider. A family doctor can refer you for further testing to find the root cause.
Acute Diarrhea: What You Need to Know
Acute diarrhea comes on suddenly and typically resolves within a few days. It is the most common form and is usually caused by an infection. Most healthy adults recover without needing medication.
The biggest risk with acute diarrhea is dehydration. When your body loses too much fluid too quickly, it cannot function properly. This risk is especially high in infants and frail or elderly individuals.
Dysenteric Syndrome
A more severe form of acute diarrhea is called dysenteric syndrome. This causes stools that contain blood and mucus. It is often a sign of a serious bacterial infection and requires prompt medical attention.
Salmonella infection is one well-known example. It spreads through undercooked poultry, eggs, and other contaminated foods. In Canada, Health Canada publishes regular food safety alerts to help Canadians avoid these infections.
How Long Does Acute Diarrhea Last?
Most cases of acute diarrhea clear up within two to four days. If your symptoms last longer than a week, it is a good idea to see a doctor. You should not ignore diarrhea that keeps going, especially if you feel very weak or dizzy.
Chronic Diarrhea: When It Does Not Go Away
Chronic diarrhea is defined as loose or watery stools that continue for more than three weeks. Unlike acute diarrhea, it rarely goes away on its own without treating the underlying cause.
Over time, chronic diarrhea can lead to malnutrition. When your digestive system cannot absorb nutrients properly, your body does not get what it needs to stay healthy. This is a particular concern for children, whose growth and development depend on good nutrition.
Malabsorption and Chronic Diarrhea
Malabsorption happens when the gut fails to absorb nutrients from food correctly. Celiac disease is a common example. People with celiac disease cannot tolerate gluten — a protein found in wheat, rye, and barley. When they eat gluten, their immune system damages the intestinal lining.
Furthermore, conditions like Crohn’s disease can cause similar damage. The intestinal wall becomes inflamed, reducing its ability to absorb nutrients. As a result, both diarrhea and weight loss can occur together.
According to the Mayo Clinic’s guide on diarrhea, identifying the underlying cause is the most important step in treating chronic diarrhea effectively.
Treatment for Chronic Diarrhea
Treatment focuses first on addressing the root cause. For example, a person with celiac disease will follow a strict gluten-free diet. Someone with IBD may need anti-inflammatory medication or other specialist care.
At the same time, proper nutrition must be restored. A registered dietitian can help you rebuild a balanced diet while managing your condition. Many provincial health plans in Canada cover dietitian consultations — check with your family doctor or provincial health authority to find out what is available to you.
How to Treat Diarrhea at Home
For most adults, mild diarrhea can be managed safely at home. The most important step is to stay well hydrated. Drink plenty of fluids throughout the day.
Staying Hydrated
Water is essential, but it alone may not replace everything your body loses. Oral rehydration solutions (ORS) are a better option, especially for children and older adults. These solutions replace lost fluids, salts, and sugars. You can find ORS products at most Canadian pharmacies without a prescription.
Avoid drinks that can make diarrhea worse, such as alcohol, caffeine, and sugary fruit juices. Sports drinks are not ideal for children and may contain too much sugar.
What to Eat
Eating bland, easy-to-digest foods can help your gut recover. The BRAT diet — bananas, rice, applesauce, and toast — is a popular short-term approach. However, it is low in nutrients, so do not follow it for more than a day or two.
In addition, probiotic-rich foods like plain yogurt may help restore healthy gut bacteria after a bout of diarrhea. Foods high in soluble fibre, such as oats and bananas, can also help firm up stools.
Should You Take Anti-Diarrheal Medication?
Over-the-counter medications like loperamide (Imodium) can slow diarrhea. However, it is not always wise to stop diarrhea too quickly. When diarrhea is caused by an infection, your body uses it to flush out the harmful germs. Stopping that process too early may slow your recovery.
Always read the label carefully and talk to a pharmacist if you are unsure. Anti-diarrheal medications are generally not recommended for young children without medical advice. The World Health Organization’s fact sheet on diarrhoeal disease provides further guidance on safe management, particularly for children in various settings.
Preventing Diarrhea in Canada
Good hygiene is the single most effective way to prevent infectious diarrhea. Wash your hands thoroughly with soap and warm water after using the bathroom and before handling food. This simple habit can stop germs from spreading.
Here are other practical prevention tips:
Cook meat, poultry, and eggs to safe internal temperatures
Refrigerate leftovers promptly and do not eat food that has been left out too long
Drink clean, treated tap water — most Canadian municipal water supplies are safe
Be cautious when travelling internationally, as water and food safety standards vary
Wash fruits and vegetables thoroughly before eating
Avoid cross-contamination between raw meat and other foods in your kitchen
If you have a known food allergy or intolerance, read ingredient labels carefully. Managing your diet is a key part of preventing diarrhea related to conditions like celiac disease or lactose intolerance.
When to See a Doctor
Most cases of diarrhea clear up on their own. However, some situations call for medical attention. Do not wait too long if you or a family member shows warning signs.
Visit your family doctor or a walk-in clinic if:
Diarrhea lasts more than two days in adults, or more than 24 hours in an infant or young child
You see blood or black, tarry stools
You have a fever above 38.5°C (101.3°F)
You feel severely dehydrated — signs include dry mouth, dizziness, and little or no urination
You have severe stomach pain or cramping
You are pregnant or have a chronic health condition
You recently returned from international travel
Babies and young children can become dehydrated very quickly. Take them to a walk-in clinic or emergency department right away if they seem unusually drowsy, have sunken eyes, or are not producing tears when crying.
If you do not have a family doctor, walk-in clinics are available across most provinces. Many provinces also offer telephone health lines — for example, Health811 in Ontario or 8-1-1 in British Columbia — where a registered nurse can give you guidance at any time of day.
Frequently Asked Questions About Diarrhea
How long does diarrhea usually last?
Most cases of acute diarrhea last between one and four days. However, diarrhea that continues for more than a week should be assessed by a doctor, as it may point to an infection or underlying condition that needs treatment.
What is the best thing to drink when you have diarrhea?
Water and oral rehydration solutions (ORS) are the best choices when you have diarrhea. ORS products, available at Canadian pharmacies, replace lost fluids and electrolytes. Avoid caffeine, alcohol, and sugary drinks, as these can make diarrhea worse.
When is diarrhea a sign of something serious?
Diarrhea can be serious if it contains blood, lasts more than two days, or comes with a high fever or severe stomach pain. Signs of dehydration — such as dizziness, dry mouth, or very dark urine — are also warning signs. In these cases, visit a walk-in clinic or your family doctor promptly.
Can stress cause diarrhea?
Yes, stress and anxiety can trigger diarrhea in some people. The gut and brain are closely connected through what is called the gut-brain axis. If you regularly experience stress-related diarrhea, speak with your family doctor, as it may be linked to irritable bowel syndrome (IBS).
Is diarrhea contagious?
Infectious diarrhea caused by bacteria, viruses, or parasites can be contagious. It spreads most commonly through contaminated food or water, or through poor hand hygiene. Washing your hands thoroughly and often is the best way to prevent spreading diarrhea to others.
What foods should you avoid when you have diarrhea?
When dealing with diarrhea, avoid greasy or fried foods, spicy dishes, dairy products (except plain yogurt), raw vegetables, and high-fibre foods like beans and lentils. These can irritate the gut and make symptoms worse. Stick to bland, easy-to-digest foods until you feel better.
Key Takeaways
Diarrhea means passing loose or watery stools more than three times a day. Acute diarrhea comes on suddenly and usually resolves within a few days. Chronic diarrhea lasts more than three weeks and needs medical investigation. The biggest risk with diarrhea is dehydration, especially in babies, young children, and elderly people. Staying hydrated with water or oral rehydration solutions is the most important home treatment. Wash your hands regularly and handle food safely to prevent infectious diarrhea. See your family doctor or visit a walk-in clinic if diarrhea lasts more than two days, contains blood, or comes with a high fever or dehydration. Always consult a healthcare professional before giving anti-diarrheal medication to children.
