Why Am I Always Constipated?

What Counts as Constipation?

Many people assume constipation just means not going to the toilet every day — but it is actually much more than that. Medically, constipation is defined (using the Rome IV criteria) as having at least two of the following for more than 25% of your bowel motions over three months: fewer than three bowel motions per week, straining to go, passing hard or lumpy stools, feeling like you have not emptied fully, feeling like there is a blockage, or needing to use your fingers to help things along.

In plain terms: if you are constantly straining, if you never feel like you have properly emptied your bowels, or if you rely on laxatives most days just to function — that is chronic constipation, even if you are technically going every day. It affects roughly one in five Australians and is more common in women and people over 65. You do not have to just live with it.

Primary Causes: Lifestyle and Diet

Most people with ongoing constipation have what doctors call functional constipation — meaning there is no underlying disease, and the issue is about how the bowel is working, driven mostly by lifestyle factors. The most common culprits are:

• Not enough fibre in your diet: Most Australians eat only 20–25 g of fibre a day, well below the recommended 25–30 g. Without adequate fibre, stools become small, dense, and hard to move along. This is the single most fixable cause for most people.
• Not drinking enough water: Fibre needs water to work — it absorbs fluid to form soft, bulky stools. Without enough fluid (ideally 1.5–2 litres of water daily), even a high-fibre diet may not help much.
• Not moving enough: Physical activity helps the bowel keep things moving through a process called peristalsis — rhythmic muscle contractions along the gut wall. If you sit for long periods each day, your gut transit slows down too.
• Ignoring the urge when it comes: Repeatedly holding on when you feel the need to go — common in busy workplaces, or when access to a toilet is inconvenient — can over time dull the signals your rectum sends. Eventually you stop feeling the urge as reliably.
• IBS with constipation (IBS-C): Irritable bowel syndrome affects how the gut moves and how it feels. People with the constipation-predominant type tend to experience bloating, abdominal discomfort, and slow bowels — often made worse by stress and certain foods.

Medications That Cause Constipation

A surprisingly wide range of common medications can slow the bowel as a side effect. If your constipation started around the same time you started a new medication, that connection is worth raising with your doctor.

• Opioid pain relievers (morphine, oxycodone, codeine): Opioid-induced constipation is very common and can be severe. It often needs specific management — sometimes a different type of laxative or a medication that counteracts the opioid's effect on the bowel.
• Iron supplements: Oral iron tablets are a frequent cause of constipation, especially at higher doses. Taking them every second day instead of daily, or switching to a gentler formulation, can sometimes help.
• Blood pressure medications (calcium channel blockers) such as amlodipine and diltiazem relax smooth muscle throughout the body — including in the bowel wall, which slows things down.
• Anticholinergic medications: These include certain bladder medications, some antihistamines, older antidepressants, and some antipsychotics.
• Some antacids — particularly those containing aluminium or calcium.

Please do not stop any prescribed medication without talking to your doctor first — but do bring up the constipation. Sometimes a simple switch to an alternative works well.

Secondary Causes: Underlying Medical Conditions

When constipation has been going on for a long time, is hard to manage with lifestyle changes, or comes with other symptoms, it is worth checking whether an underlying medical condition might be involved. Your GP can arrange blood tests and further investigations to look for these.

• Underactive thyroid (hypothyroidism): When the thyroid is not producing enough hormone, your metabolism slows — including your gut. You might also notice fatigue, weight gain, feeling the cold more than usual, and dry skin.
• Long-standing diabetes: Diabetes that has not been well controlled over many years can damage the nerves that coordinate bowel movement (a process called autonomic neuropathy). This is sometimes called diabetic enteropathy.
• Parkinson's disease: Constipation is often one of the earliest signs of Parkinson's, sometimes appearing years before the movement symptoms that most people associate with the condition.
• High calcium in the blood (hypercalcaemia): Elevated calcium, which can be caused by overactive parathyroid glands among other things, can slow the bowel.
• Bowel cancer: A new change in bowel habit — especially if you are over 50 — should always prompt a check to exclude a tumour causing a narrowing in the bowel. This is not the most likely cause, but it is the most important one not to miss.
• Pelvic floor dysfunction: Some people have constipation because the pelvic floor muscles do not relax properly when they try to open their bowels — a condition called dyssynergic defaecation. Rectal prolapse (where the bowel slides down on itself) can also cause a very similar obstruction feeling. These conditions need specialist assessment to identify and treat.

Practical Changes to Try This Week

The Role of Laxatives

Laxatives can provide real short-term relief while you work on your diet and lifestyle. They are not a long-term solution for most people — but that does not mean they are bad or harmful. Some people, particularly those taking opioid pain relief or living with a neurological condition, genuinely need laxatives on an ongoing basis, and that is perfectly okay.

Osmotic laxatives (such as Movicol, Osmolax, and lactulose) work by drawing water into the bowel and softening the stool. They are gentle, safe to use for longer periods, and a good first choice for most people. Stimulant laxatives (such as senna and bisacodyl) stimulate the bowel muscles to contract and are better suited to short-term use. Bulking agents — like psyllium husks (Metamucil) or Benefibre — add bulk to the stool and work best when you are also drinking plenty of water.

When to See Your GP or a Specialist

Most mild to moderate constipation can be managed at home with the changes described above. But please see a doctor promptly if any of the following apply:

• Your constipation is new or has changed recently, particularly if you are over 50
• You notice blood in or on your stool
• You are losing weight without trying
• You have a close family member who has had bowel cancer
• You have severe abdominal pain or vomiting along with the constipation
• You have genuinely tried dietary changes and laxatives for four to six weeks and things have not improved

A colorectal surgeon can look for structural causes of constipation, perform a colonoscopy where it is needed, and identify conditions like pelvic floor dysfunction — which can be treated very effectively with biofeedback therapy once it has been properly diagnosed.

Constipation and Its Complications

Chronic constipation is more than just uncomfortable. Years of straining raises the pressure inside the rectum and the anal canal, and over time this can lead to haemorrhoids (enlarged blood vessels around the anus), anal fissures (small, painful tears), and in some cases rectal prolapse (where the bowel slides down and protrudes outside the body). Some people eventually develop faecal impaction — where a hard lump of stool gets stuck in the rectum and physically cannot come out without help. When this happens, liquid stool can leak around the blockage, causing what looks like diarrhoea — which is often confusing until the impaction is found and treated.

Addressing constipation early protects you from these complications. See our articles on constipation and haemorrhoids and constipation and anal tears for more detail.

Frequently Asked Questions