IBS, IBD, UC and Bowel Cancer: Understanding Your Intestinal Symptoms

Introduction

Problems with the intestines are among the most common reasons people visit their GP in the UK. Yet bowel symptoms can be difficult to interpret, symptoms that feel alarming often turn out to be functional (irritable bowel syndrome), while those that seem minor can occasionally signal something more serious. This article helps you understand the difference between IBS, IBD (including Crohn’s and ulcerative colitis), and the symptoms that need prompt investigation.

Intestine Symptoms: An Overview

The intestines can produce a wide range of symptoms depending on which part is affected and what is causing the problem. Common symptoms include:

Cramping or colicky abdominal pain
Diarrhoea or constipation (or alternating between the two)
Bloating and excessive wind
Urgency to open the bowels
Mucus in the stool
Blood in the stool (always requires investigation)
Feeling of incomplete emptying after opening the bowels
Unexplained weight loss or fatigue

The tricky part is that many of these symptoms overlap between functional disorders (IBS) and organic disease (IBD, bowel cancer). This is why ongoing, changing, or worsening symptoms, especially in those over 45, should always be assessed by a GP.

IBS: Irritable Bowel Syndrome

IBS affects an estimated 10–15% of the UK population and is more common in women. It is a functional disorder, meaning the gut looks structurally normal but doesn’t behave normally. IBS is typically diagnosed when other causes have been excluded.

What Causes IBS Flare-Ups?

The triggers are highly individual, but the most frequently reported include:

Certain foods, particularly those high in fermentable carbohydrates (FODMAPs)
Stress and anxiety, the gut-brain axis is well established in IBS
Hormonal changes, many women find symptoms worsen around menstruation
Infections, post-infectious IBS can develop after a gut illness such as food poisoning or a gastric bug
Irregular eating habits and rushed meals
Antibiotics, which can disrupt the microbiome

How to Test for IBS at Home

While there is no single test for IBS, a structured self-assessment based on the Rome IV criteria can indicate whether IBS is likely. Read: How to Test for IBS at Home: Symptoms, Self-Assessment and Next Steps

The FODMAP Diet for IBS

The low-FODMAP diet was developed by researchers at Monash University and is now supported by the NHS as the most evidence-based dietary intervention for IBS. FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, a group of short-chain carbohydrates that are poorly absorbed in the small intestine and fermented by bacteria in the colon, causing gas, bloating, and altered bowel habits.

High-FODMAP foods to reduce initially:

Wheat, rye, and barley
Onions, garlic, and leeks
Beans and lentils
Milk, soft cheeses, and ice cream (lactose)
Apples, pears, mangoes, and stone fruits
Honey and foods containing fructose or sorbitol

Lower-FODMAP foods generally better tolerated:

Rice, oats, and gluten-free products
Carrots, courgette, cucumber, lettuce, and tomatoes
Firm tofu and eggs
Hard cheeses, lactose-free dairy
Blueberries, strawberries, grapes, and oranges
Plain meats and fish

The FODMAP diet is intended as a short-term elimination protocol (typically 2–6 weeks), followed by structured reintroduction to identify individual trigger foods. Working with a registered dietitian is ideal.

IBD: Inflammatory Bowel Disease

IBD is distinct from IBS, it involves genuine inflammation and, in the case of Crohn’s disease, can affect any part of the digestive tract from mouth to anus, whereas ulcerative colitis is confined to the colon and rectum.

Ulcerative Colitis (UC) Symptoms

UC typically causes:

Bloody diarrhoea, often the most characteristic symptom
Cramping lower abdominal pain, particularly on the left side
Urgency and frequency to open the bowels
Fatigue and, during flares, fever
Weight loss during active disease
Extra-intestinal symptoms: joint pain, skin rashes, eye inflammation

UC is a lifelong condition that requires proper medical management. Herbal and dietary approaches can complement conventional treatment but should not replace it.

Crohn’s Disease Symptoms (IBD)

Crohn’s can be harder to pin down because it can affect any section of the GI tract. Typical symptoms include:

Abdominal pain (often in the lower right abdomen where the ileum meets the colon)
Chronic diarrhoea, may or may not contain blood
Fatigue and malaise
Mouth ulcers
Anal fissures, fistulae, or abscesses
Fever and unintentional weight loss during active disease

Colon Pain: What Left-Side and Right-Side Pain Might Mean

Left-side colon pain (the descending colon and sigmoid colon lie here) is associated with:

UC (affects from the rectum upwards)
Diverticular disease (very common in UK adults over 60)
Constipation or trapped wind
Ovarian issues in women (referred pain)

Right-side colon pain (the cecum and ascending colon) may suggest:

Crohn’s disease (often affects the terminal ileum and right colon)
Appendicitis (central pain moving to the lower right, seek urgent care)
Irritable bowel

Any new, severe, or persistent abdominal pain on either side should be assessed by a GP, particularly if accompanied by fever, vomiting, or rectal bleeding.

Bowel Cancer Symptoms: What to Look For

Bowel cancer (colorectal cancer) is the fourth most common cancer in the UK, with around 43,000 new cases each year. The good news is that when caught early, it is very treatable. Knowing the warning signs is essential.

Symptoms that should prompt urgent GP assessment:

A persistent change in bowel habit lasting three weeks or more, especially looser stools or going more often
Blood in the stool without an obvious cause (such as haemorrhoids)
Unexplained weight loss
Extreme and unexplained fatigue
A lump in the abdomen
Pain or discomfort in the abdomen that doesn’t go away

The NHS offers bowel cancer screening to everyone aged 50–74 in England via the faecal immunochemical test (FIT). If you receive a kit, use it, it saves lives.

Do not attribute persistent rectal bleeding or bowel changes to haemorrhoids without first ruling out cancer with your GP.

Foods to Help You Go: Dietary Support for Constipation

Constipation is a common accompaniment to bowel conditions, IBS, and simply a low-fibre diet. The following dietary measures help maintain regularity:

Increase soluble fibre: oats, psyllium husk, flaxseeds, apples, and pears
Increase insoluble fibre: wholegrain bread, bran, vegetables, and beans
Drink plenty of water: at least 1.5–2 litres per day, dehydration is a major driver of constipation
Move your body: even a 30-minute daily walk significantly improves bowel transit time
Don’t ignore the urge: habitually delaying defecation makes constipation worse over time

Herbal Laxatives

For short-term support, certain herbs have been used for centuries as gentle bowel stimulants:

Psyllium husk: the gold standard bulk-forming fibre: Psyllium Husk: The Gold Standard Fibre
Senna: a stimulant laxative for short-term use: Senna Leaf: The Potent Herbal Laxative
Cascara bark: Cascara Bark: The Sacred Bark Laxative

Note: stimulant laxatives are not intended for long-term daily use. Persistent constipation warrants investigation.

Herbal Support for Bowel Inflammation

For those with IBD or inflammatory bowel conditions, certain herbs have evidence for reducing gut inflammation and supporting mucosal healing:

Slippery elm: Slippery Elm: The Supreme Gut Soother
Marshmallow root: Marshmallow Root: The Deep Gut Lining Healer
Agrimony: gentle astringent for diarrhoea: Agrimony: Britain’s Hedgerow Healer
Turmeric: powerful anti-inflammatory with bowel benefits: Turmeric: Nature’s Most Powerful Anti-Inflammatory

Always work with a qualified herbalist if you have a diagnosed inflammatory condition.