This proven exterminator won’t kill Livestock, Pets or Poultry—Gets Rats Every Time. K-R-O is made from Red Squill, a raticide recommended by U.S. Dept. Agr. (Bul. 1533). Ready-Mixed, 35c and $1.00; Powder, 75c. All Druggists. Results or Your Money Back. K-R-O Company, Springfield, O.


  1. Neil Russell says: December 15, 20099:02 pm

    And I thought the only way to get rid of rats without poison was to vote them out

  2. StanFlouride says: December 15, 200911:20 pm

    I am quite surprised to discover that this is a form of digitalis and grows in my neighbors garden. I had no idea!

  3. Tracy B says: December 16, 20092:57 pm

    This reminds me of one of Flip Wilson’s lines, “One day I put rat poison in the Coffee; Killer said that it was the first decent cup of coffee he had.”

  4. John Savard says: December 17, 20096:25 pm

    I did some Google searching. The active ingredient causes vomiting, and is a heart stimulant and diuretic. Rats are resistant to the effects on the heart, but it still causes fatal convulsions; other animals, while still sensitive to its toxicity, are able to vomit it out… but rats can’t vomit. Which would seem to mean that there should be a lot of toxic substances that affect rats only.

    For whatever reason, though, the production of this particular rat poison ended worldwide in 1980… but my reference didn’t give the specific reason.

  5. John Savard says: December 17, 20096:30 pm

    One problem is that the potency of extracts was variable, but apparently the reason many countries banned the use of this rat poison was that it was felt to be cruel to the rats. And, as noted, almost any poison could be mixed with another emetic to make something else just as specific to rats.

  6. docca says: December 20, 20099:27 am

    Actually there is a 1995 brazilian study (see here (in portuguese)) that claims rats cannot digest raw beans and can die in 3 days due to fermentation. Just crush a cup of raw beans into a thin powder, and leave it around.

    The study is a bit technical, but worth a read.

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