PEG / macrogol for constipation
Content date: 11 November 2026
Polyethylene glycol (PEG), also called macrogol, draws water into the bowel to soften stool. Constipation products may contain PEG alone or PEG with electrolytes.
Your next step
Check your written prescription and monitoring plan. If anything is unclear, ask your care team before changing a dose.
Get urgent help: Seek urgent care for severe or persistent abdominal pain, marked swelling with vomiting or inability to pass gas, or difficulty breathing.
How do I use it?
- Use the dose and mixing volume for your exact product. A common adult PEG 3350 product uses 17 g once daily, while macrogol sachets have different strengths and instructions. Dissolve powder fully as directed; do not swallow it dry. It may take one to three days to work. Aim for comfortable, soft stools and reduce or pause treatment if diarrhoea develops, following your care plan.
How do I store it?
- Keep the product away from children and follow its storage label. Drink the solution after mixing. If preparing it in advance, check the leaflet for storage and the time limit before discarding it. Ready-to-drink products have their own instructions.
What tests do I need?
- Tell your team about kidney or heart disease, a fluid restriction, or medicines affecting fluid balance. They can decide whether electrolyte or kidney tests are needed, especially with diarrhoea, dehydration or prolonged treatment.
Possible side effects: what to expect
- Not everyone gets side effects. Bloating, wind, cramps or loose stools often improve with dose adjustment under your plan. Aim for comfortable soft stools, not watery diarrhoea.
- Severe diarrhoea can cause dehydration and disturbed blood salts, especially with excessive dosing. Seek advice if diarrhoea persists; follow your permitted fluid intake. Serious allergy is possible, with frequency unspecified; breathing difficulty or facial swelling needs emergency care.
Important points
- Drink your usual permitted fluids; mixing water does not replace normal intake. Some macrogol products require other oral medicines to be separated by one hour. Check with your pharmacist. Constipation sachets and colonoscopy preparation are not interchangeable. Large doses for faecal impaction need a confirmed diagnosis and a separate clinical plan.
Brand / device: ........................ | Dose and how I take or use the medicine: ........................
Next dose: ........................ | Next blood tests: ........................
Team contact: ........................
When to get help
Seek urgent care for severe or persistent abdominal pain, marked swelling with vomiting or inability to pass gas, or difficulty breathing.
Contact your clinician for rectal bleeding, persistent diarrhoea, dehydration, or constipation that continues beyond the self-treatment period on your pack.