Zinc for Frequent Diarrhea
Zinc for childhood diarrhoea is one of the strongest supplement recommendations in global medicine. WHO and UNICEF recommend 10-20mg daily for 10-14 days, shortening episode duration and reducing recurrence.
Overview
Verdict
Consistent randomised evidence in children over six months for shorter episodes; little or no benefit under six months, and adult data are limited.
How It Works
Actions in the gut
Dosing & Protocol
WHO-aligned dosing
| Group | Dose | Duration | Notes |
|---|---|---|---|
| Infants under 6 months | 10 mg daily | 10-14 days if used | Reviews show little or no benefit; follow local guidance |
| Children 6 months to 5 years | 20 mg daily | 10-14 days | Standard WHO regimen alongside oral rehydration solution |
| Older children | 20 mg daily | 10-14 days | Give with food to reduce vomiting |
| Adults | No established regimen | - | Adult trial evidence is limited; do not extrapolate the paediatric dose long term |
Zinc supports but never replaces oral rehydration solution, which is what prevents dehydration.
Rehydration comes first
Zinc shortens the episode; it does not treat dehydration. Oral rehydration solution is the priority, and any child with sunken eyes, no tears, reduced urine output, lethargy, blood in the stool or a high fever needs medical assessment now.
Evidence
Studies linked to this pairing.
Oral zinc for treating diarrhoea in children
Lazzerini M, Wanzira H
Zinc supplementation shortens acute diarrhoea in children over six months in settings at high risk of zinc deficiency.
Zinc supplementation for acute and persistent watery diarrhoea in children: A systematic review and meta-analysis
Ali AA, Naqvi SK, Hasnain Z +7 more
Zinc supplementation resulted in a greater proportion of children who recovered from diarrhoea at last follow-up (RR = 1.07) and a reduction in the duration of diarrhoea (MD = -13.27 hours).
Safety
Do not run zinc long term at treatment doses
Treatment doses are for 10 to 14 days only. Months of high-dose zinc cause copper deficiency, anaemia and neuropathy.
Interactions & Conflicts
Interactions and cautions
| Interacts with | Severity | Mechanism | Action |
|---|---|---|---|
| Copper status | high | Prolonged high-dose zinc blocks copper absorption | Limit to the 10-14 day course; do not repeat continuously |
| Quinolone and tetracycline antibiotics | moderate | Zinc chelates the antibiotic and reduces its absorption | Separate doses by at least two hours before or four to six hours after |
| Iron supplements | moderate | Competition for shared absorption pathways in a single dose | Give at different times of day |
| Penicillamine | moderate | Mutual chelation reduces both drug and mineral absorption | Separate administration and monitor |
| Empty stomach dosing | low | Raises the likelihood of vomiting, the main adverse effect | Give with food or milk |
References
- Lazzerini M, Wanzira H. Oral zinc for treating diarrhoea in children. Cochrane Database Syst Rev (2016)
- Zinc supplementation for acute and persistent watery diarrhoea in children: systematic review and meta-analysis (2024)
- WHO/UNICEF joint statement on the clinical management of acute diarrhoea
Frequently Asked Questions
How much zinc for a child with diarrhoea?
Does it work in babies under six months?
How much shorter is the illness?
Why is my child vomiting after the dose?
Can adults take zinc for frequent diarrhoea?
Should zinc be taken continuously to prevent diarrhoea?
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.