Bristol Stool Type 6: Causes, What It Means, and When to See a GP
Fluffy pieces with ragged edges - a mushy stool
What Type 6 Looks Like and What It Means
Type 6 represents diarrhoea. The stool is mushy with ragged edges and no clear form. It indicates rapid colonic transit with insufficient time for water reabsorption. Persistent type 6 warrants investigation, particularly for IBS-D, food intolerance, or infection.
Common Causes of Type 6 Stool
- IBS-D (Irritable Bowel Syndrome, diarrhoea-predominant)
- Bacterial or viral gastroenteritis
- Food intolerance: lactose, gluten (coeliac disease)
- Bile acid diarrhoea (common after cholecystectomy)
- IBD flare (Crohn's or ulcerative colitis)
- Medications: antibiotics, metformin, PPIs, certain blood pressure drugs
- Anxiety and stress
- Alcohol excess
- Post-surgical changes
What You Can Try at Home
- -Oral rehydration: water, diluted squash, or pharmacy ORS sachets
- -Avoid dairy, fatty foods, and caffeine temporarily
- -Small, bland meals (banana, rice, plain toast, boiled potato)
- -Probiotics: Saccharomyces boulardii (S. boulardii) has good evidence for infectious diarrhoea
- -Keep a food and symptom diary to identify triggers
- -Rest and avoid dehydrating activities
Type 6 in Depth: Diarrhoea, IBS-D, and Bile Acid Diarrhoea
Type 6 is clinically classified as diarrhoea. The mushy, fluffy appearance with ragged or torn edges indicates that stool has moved through the colon too quickly for adequate water reabsorption. Transit time is typically 6-12 hours for type 6. The stool has no clear, continuous form - it is fragmented and soft-edged, distinguishing it from type 5 (which still has clear-cut separate blobs).
Persistent type 6 - lasting more than 7-14 days - requires investigation. The commonest causes in the UK are IBS-D, food intolerance (lactose, gluten), bile acid diarrhoea (often following cholecystectomy), and IBD. Occasional type 6 following a spicy meal, a period of anxiety, or a social event is common and not clinically significant.
Bile Acid Diarrhoea: A Commonly Missed Diagnosis
Bile acid diarrhoea (BAD) - also known as bile acid malabsorption - is one of the most commonly underdiagnosed causes of chronic type 6-7 diarrhoea in the UK. Bile acids are produced in the liver, stored in the gallbladder, and released into the small intestine after eating to aid fat digestion. Normally, about 95% is reabsorbed in the terminal ileum. When this reabsorption fails (due to ileal disease, post-cholecystectomy changes, or idiopathically), bile acids pass into the colon where they stimulate water secretion and accelerate motility, causing diarrhoea.
BAD affects an estimated 1% of the UK population and up to 25-35% of patients labelled with IBS-D. It is treatable with bile acid sequestrants (colestyramine, colesevelam) prescribed by a GP or gastroenterologist. If you have had your gallbladder removed and subsequently developed persistent loose stools, or if you have been diagnosed with IBS-D without a satisfactory response to standard treatment, it is worth asking your GP about testing for BAD (SeHCAT scan or empirical treatment trial).
Food Intolerances and Type 6
Lactose intolerance and non-coeliac gluten sensitivity are common causes of type 6 stools. Coeliac disease (an autoimmune condition triggered by gluten) causes flattening of the small intestinal villi, impairing nutrient absorption and often producing type 6-7 stools, along with bloating, fatigue, and weight loss. If you suspect coeliac disease, do not eliminate gluten before testing - a blood test (tTG-IgA antibody test) can only be interpreted if you are still consuming gluten. Your GP can arrange this test.
Probiotics and Type 6
Several probiotic strains have clinical evidence for managing type 6 diarrhoea. Saccharomyces boulardii CNCM I-745 (available as Florastor) has the strongest evidence for infectious diarrhoea and post-antibiotic diarrhoea. For IBS-D specifically, Bifidobacterium infantis 35624 (Alflorex) has NICE-recognised evidence and UK-based clinical trial data. See our partner resource probioticvsprebiotic.com for a full evidence review.
See also our full Diarrhoea Guide and the IBS Stool Chart guide for condition-specific management.
When to See a GP
Seek GP assessment if you notice any of the following alongside type 6 stools:
- !Type 6 persisting more than 7 days
- !Blood or mucus in the stool
- !Fever above 38.5C
- !Signs of dehydration (dry mouth, dark urine, dizziness)
- !Recent antibiotic use (risk of C. difficile infection)
- !Return from travel abroad with persistent symptoms
For full red-flag criteria including bowel cancer referral thresholds, see our Red Flags guide.
Frequently Asked Questions
Is type 6 stool always diarrhoea?+
Clinically, yes - type 6 is classified as diarrhoea because it indicates fast transit and excess water in the stool. However, a single type 6 occurrence after a large meal, alcohol, stress, or illness is very common and not medically significant. It becomes clinically relevant when it persists more than 7-14 days, occurs frequently (more than 3 times per day), or is accompanied by blood, mucus, fever, or dehydration.
What does type 6 stool mean for IBS?+
In IBS, consistent type 6 stools (more than 25% of bowel movements) classify the condition as IBS-D (diarrhoea-predominant) under Rome IV criteria. IBS-D is the subtype associated with urgency, frequency, and loose stools without blood or structural bowel disease. The NHS treatment pathway includes low-FODMAP diet, antispasmodics, loperamide as needed, and in some cases bile acid sequestrants if BAD is suspected. Our IBS Stool Chart guide covers this in full.
I have type 6 after every meal - what does that mean?+
Post-meal type 6 diarrhoea (within 20-60 minutes of eating) can indicate an overactive gastrocolic reflex, which is common in IBS-D and also in bile acid diarrhoea. It may also suggest a food-specific trigger - common culprits include lactose (dairy), fructose (fruit, honey, high-fructose corn syrup), sorbitol, and wheat in those with non-coeliac gluten sensitivity. Keeping a food and symptom diary - which our tracker supports - for two weeks can help identify patterns. Discuss persistent post-meal diarrhoea with your GP.
Can anxiety cause type 6 stool?+
Yes. The gut-brain axis is well established - the enteric nervous system (sometimes called the second brain) responds directly to emotional states. Anxiety activates the sympathetic nervous system, which can accelerate colonic motility and trigger type 6 stools. This is particularly prominent in IBS, where gut hypersensitivity amplifies the normal gut-brain response. CBT and gut-directed hypnotherapy are NICE-recommended for IBS and have strong evidence for reducing anxiety-driven diarrhoea.
Should I drink less water if I have type 6 stool?+
No - this is a common misconception. Type 6 stool is caused by fast colonic transit, not by drinking too much water. In fact, type 6 diarrhoea causes you to lose more fluid than normal, so it is important to maintain or increase hydration. Oral rehydration salts (ORS sachets from the pharmacy) replace electrolytes lost with diarrhoea more effectively than plain water. Restricting fluid intake does not slow the bowel and risks dehydration.
Updated April 2026