ReviseFCPS1
CPSP Part 1 Prep

Corrosive poisoning — Harpic, acids and alkalis

Airway first, then what not to do, then CT at 3–6 hours. Follows the WSES 2019 oesophageal emergencies guideline, with its own grades shown.

CT, not endoscopy, is the primary emergency investigation. Emergency management of caustic ingestion can be performed safely relying on computed tomographic evaluation (Grade 2A). Endoscopy is now reserved for the situations in step 4. Most of us were taught the other way round.
Every recommendation on this page carries an evidence tier. Guideline / position paper Cohort or series Case reports / expert opinion
Corrosive ingestion has a graded guideline behind it. Other poisonings in this suite will not, and we would rather show you the difference than flatten it.
National Poisons and Drug Information Centre, Jinnah Postgraduate Medical Centre (JPMC), Karachi0800-77767
WSES recommends contacting a poison control centre to evaluate the systemic toxicity of the ingested agent (Grade 2B). Reported as a round-the-clock toll-free service. Confirm the current number against your own hospital directory before relying on it in an emergency.
Decision-support only. This reproduces published guidance so you can apply it quickly. It does not replace clinical judgement, your hospital protocol, or the guideline itself. Where the guideline is silent — steroids, prophylactic antibiotics, early dilution — this tool says so rather than inventing an answer.
Clinically reviewed by Dr Syed Usama Hussain, MBBS, BSc · 05 Aug 2026.

Step 1 · Airway first

WSES 2019

Guideline / position paper

Harpic is hydrochloric acid.

Harpic Power Plus is formulated at approximately 10.5% w/v hydrochloric acid. It is a strong acid ingestion, not a "detergent" ingestion, and it should be triaged as such. Drain and oven cleaners are usually the opposite — strong alkalis — and injure by liquefactive necrosis, but the emergency pathway below is the same for both. Cohort or series

Manufacturer safety data sheet (Reckitt Benckiser)

Common questions

Should I do endoscopy or CT first after a corrosive ingestion?

CT. WSES 2019 states that emergency management of caustic ingestion can be performed safely relying on computed tomographic evaluation (Grade 2A). Contrast-enhanced CT outperformed endoscopy in detecting transmural injury and in predicting stricture. Endoscopy is now reserved for when CT is unavailable, when contrast is contraindicated, when CT interpretation is uncertain, or in children.

What is in Harpic?

Harpic Power Plus is formulated at approximately 10.5% w/v hydrochloric acid. It is a strong acid ingestion and should be triaged as one, not treated as a detergent ingestion.

The patient has no mouth burns and no pain. Can I discharge them?

No. WSES states that clinical symptoms do not correlate reliably with the extent of gastrointestinal damage, and that the absence of pain and of oral lesions does not rule out life-threatening gastrointestinal injuries. Liquids in particular transit quickly and can leave an unremarkable mouth with a destroyed stomach.

Should I neutralise the acid with something alkaline?

No. Acid–base neutralisation is exothermic, so it adds a thermal burn to the chemical one and generates gas in an already-injured stomach.

Should I do gastric lavage or give activated charcoal?

Neither. The AACT/EAPCCT position paper states gastric lavage should not be performed routinely, if at all. Activated charcoal is for poisons known to adsorb to charcoal — corrosives are not — and it coats the mucosa, obscuring the endoscopic assessment you may need. Inducing vomiting is named explicitly as contraindicated after a corrosive.

When should the CT be done?

CT of the neck, thorax and abdomen 3–6 hours after ingestion, before and after intravenous non-ionic contrast at 2–3 mL/s, 2 mL/kg, with an 18–25 second acquisition and a 90 second scan delay.

What CT finding means the patient needs emergency surgery?

Absence of post-contrast wall enhancement. WSES states this is the main sign of transmural digestive necrosis, and its presence at any level — oesophagus, stomach, duodenum, bowel or colon — is an indication for emergency surgery.

When should stricture dilation be started?

Endoscopic dilation should be attempted 3–6 weeks after ingestion in patients with fewer than 3 short strictures under 5 cm (Grade 2A), at intervals of 1–3 weeks. Three to five sessions are expected to give satisfactory results, and reconstruction is considered after 5–7 failed attempts.

Do corticosteroids help?

WSES does not make a recommendation on steroids for caustic injury, and this tool does not either. Where the guideline is silent we say so rather than filling the gap.

Clinically reviewed by Dr Syed Usama Hussain, MBBS, BSc
MBBS, BSc — active medical practitioner in Pakistan. Graduated from Federal Medical & Dental College, Islamabad (2021) and completed a one-year clinical internship at the Pakistan Institute of Medical Sciences (PIMS), Islamabad (2022).
Sources

Background reading — why CT replaced endoscopy, what a normal-looking mouth does not tell you, and the five things never to do: Harpic and corrosive ingestion.

Also in this suite: wheat pill and rat poison, copper sulphate and anticoagulant rat poison. See the rest of our clinical tools.