Constipation affects around 1 in 7 UK adults and is one of the most common reasons people visit a pharmacy. While it’s rarely serious, it can be painful, debilitating and significantly affect quality of life. Understanding its causes helps you choose the right solution.
What Is Constipation?
Constipation is technically defined as fewer than 3 bowel movements per week, but the clinical picture is broader: stools that are hard, dry or pellet-like; straining or pain during defecation; a sensation of incomplete emptying; or needing manual assistance to pass stool. “Normal” bowel habit varies widely between individuals — anywhere from 3 times a day to 3 times a week can be normal. What matters is whether your pattern has changed and whether it’s causing symptoms.
Why Does Constipation Happen?
The large intestine absorbs water from the stool as it passes through. If transit is slow, more water is absorbed and stools become drier and harder. Common causes: insufficient dietary fibre (the UK average intake is 18g vs the recommended 30g), inadequate fluid intake, sedentary lifestyle, ignoring the urge to defecate (especially common in busy adults), medications (opioids are the most potent, but iron tablets, calcium channel blockers, antacids with aluminium or calcium, antidepressants, and antipsychotics also cause constipation), hypothyroidism, pregnancy, irritable bowel syndrome, and simply the ageing process (bowel motility naturally slows).
The Four Types of Laxative
Bulk-forming laxatives (ispaghula husk: Fybogel; methylcellulose: Celevac) — mimic dietary fibre, absorbing water and increasing stool bulk and softness. The gentlest and most physiological option; closest to how the body ideally works. Take 1–3 days to work. Must be taken with plenty of water. First choice for most people. Not suitable for faecal impaction.
Osmotic laxatives (macrogol/PEG: Movicol, Laxido; lactulose) — draw water into the bowel by osmosis. Macrogols are more effective than lactulose and cause less gas and bloating. Very effective for acute and chronic constipation and for faecal impaction (higher doses). Onset 24–48 hours for macrogols; 2–3 days for lactulose.
Stimulant laxatives (senna: Senokot; bisacodyl: Dulcolax) — stimulate the nerves of the bowel wall, increasing muscular contractions. Fast-acting (6–12 hours orally; 20–60 minutes rectally). Best for short-term use or when a predictable result is needed. Avoid daily use long-term — the old concern about “bowel laziness” is probably overstated, but dependence is possible.
Stool softeners (docusate: Norgalax, DulcoSoftener) — reduce surface tension, allowing water to penetrate hardened stool. Mild effect; often combined with stimulants. Useful when straining must be avoided (post-surgery, haemorrhoids, cardiac conditions).
Lifestyle First
Before reaching for laxatives, address the fundamentals: increase fibre (add vegetables, legumes, wholegrains, prunes), drink at least 1.5–2 litres of fluid daily, exercise — even regular walking significantly stimulates bowel motility, establish a routine (try sitting on the toilet at the same time each day, ideally 20–30 minutes after breakfast when the gastrocolic reflex is strongest), use a footstool to bring your knees above hip height (squatting position is mechanically superior for defecation).
Browse Constipation treatments at Huncoat Pharmacy. Related: IBS Guide, Gut Health Guide.
At Huncoat Pharmacy: Pharmacy First, Browse constipation relief products.