On a bottle of distilled water, there is a paragraph called First Aid that reads:

In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. If swallowed, rinse mouth with water (only if the person is conscious).

  1. What is the point of rinsing eyes with water after distilled water contact with the eyes?
  2. Why does one need to rinse mouth with water after swallowing distilled water?
  • 5
    Because corporate attorneys.
    – Carey Gregory
    Commented Jul 23, 2023 at 2:39

1 Answer 1


The comment from @Carey Gregory is certainly correct. But why? Well, corporate attorneys have a responsibility to protect the corporation from lawsuits, even the frivolous, ridiculous, in complete defiance of logic complaints. I could imagine an attorney asked 'what would happen if someone splashed this distilled water in their eyes?'. The scientist would say 'nothing, it's just water'. The attorney, having experience with morons with access to opposing attorneys, says 'but what if someone deluged their eyes with this product for an hour straight?'. The scientist might say, 'well, that would probably cause some minor eye irritation to the moron because of the expected difference in pH of the distilled water versus the natural eye lubricant pH, but that would happen with plain tap water as well...'. To which the attorney would recommend a standard warning label including 'rinse eyes with water' to avoid having to deal with the future lawsuit for eye irritation caused by splashing distilled water into a moron's eyes. Yes, it's crazy, but so are people and their attorneys.

Eye irritation can occur because of differences in the pH due to the cellular absorption of water in higher versus lower pH. Saline solution for wearers of contacts is buffered to a specific range of pH for this reason. The difference in pH values of distilled versus tap water can be seen here: https://www.medicalnewstoday.com/articles/327185#how-to-testhttps://www.medicalnewstoday.com/articles/327185#how-to-test and here: https://sciencing.com/ph-distilled-water-4623914.html

Interestingly, in the second article, is the statement that "Pure distilled water should be neutral with a pH of 7, but because it absorbs carbon dioxide from the atmosphere, it's actually slightly acidic with a pH of 5.8.". So, putting distilled water into your eyes is essentially putting acid into your eyes, in the perspective of a risk management-minded attorney.

Personally, I would not rinse my eyes with anything except saline solution intended for eyes. If splashed with anything other than that saline solution, I would rinse with saline solution intended for eyes. But, thank you, to all the risk managers and attorneys out there protecting us from the morons.

  • +1 but I would have thought osmolarity would be a more important issue then pH. Bathing exposed tissue in distilled water is going to cause the cells in that tissue to absorb water and expand, possibly damaging them.
    – Carey Gregory
    Commented Aug 5, 2023 at 3:06
  • Thank you for your detailed answer! How about swallowing distilled water? Will rinsing the mouth with water after swallowing distilled water really help in any sense?
    – Zuriel
    Commented Aug 5, 2023 at 3:17
  • @Zuriel No, there's nothing that needs to be helped.
    – Carey Gregory
    Commented Aug 5, 2023 at 4:34

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