Protocol · WHO snakebite guidance
Snakebite: first aid and referral
Snakebite is a medical emergency, but about half of bites by venomous snakes inject no venom. The aims are to keep the person still, avoid harmful traditional methods, recognise envenoming early, and get the person to antivenom and resuscitation quickly. Treat every suspected bite as potentially serious and observe.
- Based on WHO snakebite guidance
- For doctors, clinical officers, nurses and community health workers
- Reviewed October 2026
1Who / when
- Anyone bitten, or possibly bitten, by a snake; and anyone with unexplained bleeding, drooping eyelids, weakness or collapse in a place with venomous snakes (some bites are not noticed, for example kraits at night).
- Snakebite is a red triage category: see the person immediately.
- Species and antivenoms differ by region: follow your national or regional snakebite guideline.
2Red flags: refer now
- Paralysis: drooping eyelids, double vision, difficulty swallowing or speaking, weak neck, breathing difficulty.
- Bleeding: from gums, nose, old wounds or the bite; blood in vomit, urine or stool; blood that does not clot in 20 minutes.
- Shock: low BP, fast weak pulse, cold skin, fainting.
- Dark brown or black urine, or passing little urine.
- Swelling spreading fast, or over more than half the bitten limb.
Signs of envenoming: resuscitate and transferClear the airway, give oxygen, put in an IV line and arrange transfer to a facility with antivenom and the ability to ventilate. Breathing failure can come on quickly.
3Assess
- Ask: where on the body, when, what were you doing, what did the snake look like, is there a photo? Never send anyone to catch or kill the snake; a dead snake can still bite, so do not handle it.
- Examine the bite and limb: swelling, tenderness, tender lymph nodes, blisters, bleeding, early dead tissue.
- General: BP (including lying and standing), pulse, breathing, gums and nose for bleeding, eyelids, eye movements, swallowing, neck strength, level of consciousness.
- Monitor these signs every hour.
- Urine: colour, dipstick for blood.
20-minute whole blood clotting test (20WBCT)
- Put 2 mL of fresh venous blood in a new, clean, dry, ordinary glass tube.
- Leave it undisturbed for 20 minutes.
- Tip it once. If the blood is still liquid, the blood is not clotting: venom is affecting clotting and antivenom is needed.
Plastic tubes, or glass washed with detergent, give false results. If in doubt, repeat alongside blood from a healthy person.
4Classify
| Picture | Classify as | Action |
|---|---|---|
| Paralysis, breathing difficulty, shock, spontaneous bleeding, non-clotting 20WBCT, dark urine or little urine | Systemic envenoming | Antivenom if available and staff can manage reactions; otherwise transfer now |
| Swelling over half the limb (no tourniquet) within 48 hours, or rapid spread, or swelling after a finger or toe bite, or tender enlarged lymph nodes | Significant local envenoming | Antivenom indicated; transfer |
| Bite, no signs yet | Possible envenoming | Observe closely with hourly checks and repeat 20WBCT; do not discharge early |
5Treat
First aid (anyone can do this)
- Reassure the person: many bites inject no venom, and treatment works.
- Keep the whole person still, lying down (recovery position if they may vomit). Splint or sling the bitten limb. Any movement spreads venom.
- Where bites by snakes that cause paralysis are possible, a firm pressure pad over the bite (or a broad pressure bandage up the limb, if you are trained) can slow venom spread. Not for bites that mainly cause local swelling and tissue damage.
- Note the time. Remove rings and tight items from the limb.
- Transport quickly and safely, keeping the limb still.
Do notNo tight tourniquets. No cutting, sucking, burning, electric shocks, herbs, ice or 'snake stones'. If a tight band is already on, do not remove it until you are with staff who can resuscitate and antivenom has been started.
At the clinic
- Antivenom is the only specific treatment. Give it only if indicated, and only where adrenaline is ready and staff can recognise and treat anaphylaxis. If you have none, transfer.
- Antivenom reaction: stop the antivenom; give adrenaline 0.1% (1 mg/mL) 0.5 mg IM in adults (0.01 mg/kg in children); repeat every 5 to 10 minutes if needed. Restart antivenom cautiously once settled.
- Shock: cautious IV fluid, 250 to 500 mL of 0.9% saline in adults, then reassess.
- Pain: paracetamol by mouth. No aspirin or NSAIDs (bleeding risk); avoid IM injections when blood is not clotting.
- Wound: leave alone. If dead, interfered with or infected: antibiotics and tetanus protection.
6Follow-up
- Observe every bite closely, with hourly checks, because envenoming can be delayed.
- After antivenom: repeat 20WBCT about 6 hours after the dose; still not clotting means more antivenom is needed.
- Late reactions (fever, rash, joint pain) can appear 5 or more days after antivenom: ask the person to return.
7Counsel
- Wear shoes and use a torch at night; sleep on a raised bed under a tucked-in mosquito net.
- Keep the area around the house clear; store grain away from where people sleep (rodents attract snakes).
- If bitten: keep still, come to the clinic quickly, and do not use traditional treatments.
Many snakebites do not inject poison, and there is good treatment. Keep still, and let us watch you closely for the next hours.
8When to refer
- Immediately: any sign of envenoming, especially paralysis or breathing difficulty, bleeding or shock, if antivenom or ventilation is not available at your facility.
- Blood still not clotting 6 hours after antivenom, or substantial bleeding.
- Progressive weakness or breathing difficulty.
- Little or no urine, or dark urine (kidney injury).
- Severe local swelling or dead tissue, or a tight tourniquet already applied.
9Sources
- World Health Organization Regional Office for South-East Asia. Guidelines for the management of snakebites, 2nd edition. 2016 (ISBN 9789290225300). First aid, assessment, 20WBCT, antivenom indications, reaction treatment, analgesia and management at the health post.
- World Health Organization and International Committee of the Red Cross. Basic emergency care: approach to the acutely ill and injured. 2018. Snakebite in the ABCDE approach; bandaging and immobilisation skill.
- World Health Organization Regional Office for Africa. Guidelines for the prevention and clinical management of snakebite in Africa. 2010. Regional guidance for African species; follow it where it applies.
- World Health Organization, International Committee of the Red Cross and Médecins Sans Frontières. Interagency Integrated Triage Tool. 2023. Snakebite as a red criterion.
Adapted from WHO guidance; not endorsed by WHO. This page paraphrases and adapts the WHO publications listed under Sources, which are licensed CC BY-NC-SA 3.0 IGO; the adapted text is shared under the same licence for non-commercial education. Reasoning GP is not affiliated with WHO or any other organisation named here. Use it alongside your national guidelines, essential medicines list and formulary, and your clinical judgement. Doses are given only where they come from a WHO source; otherwise follow your national guideline or formulary.