What is IBS?
Irritable Bowel Syndrome (IBS) is one of the most common gut disorders in the world, affecting an estimated 7–15% of people. If you're living with it, you already know how disruptive it can be — the cramping, the unpredictability, the anxiety of not knowing how your gut will behave today.
The good news: IBS doesn't damage your digestive tract or increase your risk of colon cancer. But that doesn't make the symptoms any less real or any less worth addressing.
What are the symptoms of IBS?
IBS is typically indicated by two or more of the following:
- Abdominal pain
- Bloating
- Excessive wind
- Changes in bowel frequency — going more or less than usual
- Changes in stool consistency — very loose or very hard
A formal diagnosis should always be made by a doctor, not self-diagnosed.
How is IBS diagnosed?
There's no single lab test or scan that confirms IBS. Instead, your doctor will assess your symptoms — often using the Rome IV criteria, which looks for:
- Abdominal pain (occurring at least one day per week over the past three months)
- Pain that is linked to going to the toilet (either relieving or worsening it)
- A change in how often you go, or what your stool looks like
Other possible symptoms include nausea, cramping, bloating, and excess wind.
IBS subtypes
Depending on your most dominant symptoms, IBS may be classified as:
- IBS-D — diarrhoea predominant
- IBS-C — constipation predominant
- IBS-M / IBS-A — mixed or alternating between both
What causes IBS?
The gut is complex, and so is IBS. There's rarely a single cause — instead, several factors tend to interact to produce the symptoms.
Abnormal intestinal muscle function
Normally, the muscles lining your intestine contract and relax rhythmically, moving food and waste through at a steady pace. In IBS, this rhythm is disrupted and becomes either too slow or too fast. Overactive muscles move food too quickly, leading to diarrhoea. Sluggish muscles do the opposite, causing constipation. Spasms create cramping, bloating, and trapped gas. The underlying driver is often disrupted gut-brain communication.
Gut hyper-sensitivity
Some people with IBS have a digestive system that is more reactive — where normal digestive activity registers as pain or discomfort. This heightened sensitivity can develop after a gut infection; the initial inflammation leaves the gut primed to overreact long after the illness has passed.
Gut microbiome imbalance
A healthy gut relies on a balanced community of bacteria. In IBS, this balance may be disrupted — with some bacteria overgrowing and others depleted — interfering with digestion and gut function.
The gut-brain connection
The gut and brain are in constant communication. Stress, anxiety, and difficult life events don't just affect your mood — they directly influence how your gut behaves. Stress can slow digestion, increase cramping and wind, alter the microbiome, and compromise the gut lining. And because gut discomfort itself causes stress, the cycle can become self-reinforcing.
Hormones and gut chemistry
Your gut contains over 600 million neurons, forming what's known as the enteric nervous system. This system regulates digestion by releasing hormones and neurotransmitters. When it's disrupted, the result can be irregular digestion, heightened sensitivity, and IBS symptoms.
Food triggers
Once the gut is sensitised — for any of the reasons above — certain foods can make symptoms significantly worse. This isn't the same as a food allergy; it's the gut responding to triggers in an already irritated system.
A note on symptoms
If your symptoms include blood in your stool, unexplained weight loss, or anything that concerns you, speak to your doctor promptly. These can occasionally indicate something more serious that warrants investigation.
Living with IBS
IBS can feel unpredictable, but it's also one of the most well-researched gut conditions — which means there are real, evidence-based ways to manage it. Identifying and reducing your food triggers, supporting your gut microbiome, and addressing the stress side of the gut-brain connection can all make a meaningful difference to how you feel day to day.
You don't have to just live with it. Read our guide to treating IBS for practical, research-backed next steps or browse our gut health range, formulated with IBS in mind.
