I've heard the above mentioned many times growing up that chewing your fingernails will expose you to more germs than to licking a public toilet seat.

Apologies for the provacative title, but here are quotes from the top 4 Google results from Australia:

  • Cause biting your fingernails is really worse then licking a dirty toilet seat!
  • Did you know that biting your nails is the bacteria equivallent of licking the toilet seat? It's true.
  • Biting your nails is like licking the doorknob of a PUBLIC restroom.
  • 24
    Everything that has to do with germs is always measured in terms of whether or not it is worse than licking a toilet seat. From the variety of claims I've heard, it would appear that toilet seats are not very high up on the toplist of germ-infested lickables. I wouldn't be surprised if there was nothing more to this story than the simple observation that a toilet seat mostly has contact with, well, legs, that have spent most of their time since last shower inside a pair of pants, whereas your hands has touched coins, other people, and you probably scratched your balls as well! May 18, 2011 at 9:58
  • 2
    @David Hedlund - Most public toilets I've seen I wouldn't even sit on. Most people don't have good aim and there's the occassional fellow with the grumbly stomach.
    – going
    May 18, 2011 at 10:25
  • 5
    AFAIK a doorknob in a public restroom would have more bacteria than the toilet seats there. Hands and mouths have the most bacteria. May 18, 2011 at 10:49
  • 2
    @David: I also remember reading that the place with the least germs in a public restroom generally is the toilet seat, and the doorknob being amongst the worse.
    – Borror0
    May 18, 2011 at 12:03
  • 3
    @Martin: the thing about the mouth being among the places with the most bacteria is telling. Next time someone makes a comparison like this, I'll counter: "If you were to lick a toilet seat, then you would contaminate it" May 19, 2011 at 7:49

1 Answer 1


Obviously, clean nails are better than dirty toilets and vice versa, therefore to remove doubt and clarify the context, I will present studies of how easy it is to keep each clean.

Toilet bowls

On the basis of the evidence presented above it is considered that toilet flushing is sufficient to remove most of the microbial contamination from the toilet bowl, and the surface of the bowl, provided that an adequate amount of water (minimum 15-17 litres of water) is used for flushing. Since toilet flushing does not achieve decontamination under the flushing rim of the toilet, the toilet requires regular application of a hygiene procedure which will maintain a low level of contamination in the toilet bowl and under the flushing rim to prevent build up of biofilms or scale which could harbour pathogens.
source, page 55


The subungual region contains large numbers of bacteria which are largely inaccessible during hand hygiene practices and are therefore difficult to clean compared with the rest of the hands.


There are several reports linking fingernails with the transmission of nosocomial infection. One study linked an outbreak of postoperative Serratia marcescens infection with a nurse, suggesting that artificial fingernails may have facilitated the transfer of S. marcescens from home. In another study, an outbreak of Pseudomonas aeruginosa in a neonatal intensive care unit was associated with two nurses with long fingernails, one artificial and one natural.

It is therefore reasonable to conclude that nails are much more likely to contain pathogens than toilet seats, provided that a reasonable amount of cleaning is performed: hands are washed normally, toilets are flushed and hygenised as normal practice.

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