Toxicity of alkaline solutions.

We examined the question of what determines the toxicity of alkaline solutions--pH, viscosity, or other factors. Our experiments have identified pH measurement as the simplest and most easily measured parameter for determining initial management of caustic ingestions. Viscosity is not a clinically useful measurement. The closer to 14 the pH measures, the more destructive the caustic. Non-lye solutions known to cause esophageal ulceration have a pH of 12.5 to 13.5. Most cases of deep ulceration going on to stricture formation involve lye solutions of pH 14. The critical pH that causes esophageal ulceration is 12.5, and thus a patient ingesting a substance with a pH greater than 12 should be followed closely for the possibility of esophageal ulceration.