Nitrate and the blue blood
Potassium nitrate (saltpetre, sal prunella, the pills of niter), sodium nitrite in curing salts, and nitrate-rich well water and vegetables in infants.
Nitrate and the blue blood: how soon does it show?
An hour or two.
How does it run?
Gastritis and vomiting from the salt; then, as the mouth’s bacteria and the gut reduce nitrate to nitrite, the oxidation of haemoglobin to methaemoglobin, which cannot carry oxygen: slate-blue lips and skin, headache, breathlessness, and at levels above half, coma and death. Infants, whose haemoglobin is more easily oxidised, were the victims of well water (“blue baby”). Thirty grams of saltpetre has killed an adult.
What is done for it?
Methylene blue, which reduces the methaemoglobin back; oxygen.
Historical and descriptive, not medical advice. In a poisoning, call a poison centre or emergency services.
Which substances in the database cause it?
Sources
- Goldfrank’s Toxicologic Emergencies, 11th ed. (2019), “Methemoglobin inducers.” Standard reference work
- Comly, H. H. (1945). “Cyanosis in infants caused by nitrates in well water.” JAMA 129. Verified against its record · doi:10.1001/jama.1945.02860360014004