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Most often toxicologists use Lethal Dose and Lethal Concentration to gauge the toxicity of most chemicals; evaluated on many kinds of animals but most often testing is done with rats and mice. The LD50 or LC50 is one way to measure the short-term poisoning potential (acute toxicity) of a material.

It is usually expressed as the amount of chemical administered (e.g., milligrams) per 100 grams (for smaller animals) or per kilogram (for bigger test subjects) of the body weight of the test animal. The LD50 can be found for any route of entry or administration but dermal (applied to the skin) and oral (given by mouth) administration methods are the most common.

Please see the scale on toxicity tabulated by Hodge & Sterner.

Table: Toxicity Classes: Hodge and Sterner Scale

Routes of Administration
    Oral LD50 Inhalation LC50 Dermal LD50  
Toxicity Rating Commonly Used Term (single dose to rats) mg/kg (Exposure of rats for 4 hours) ppm (single application to skin of rabbits) mg/kg Probable Lethal Dose for Man
1 Extremely Toxic 1 or less 10 or less 5 or less 1 grain
(a taste, a drop)
2 Highly Toxic 1-50 10-100 5-43 4 ml (1 tsp)
3 Moderately Toxic 50-500 100-1000 44-340 30 ml (1 fl. oz.)
4 Slightly Toxic 500-5000 1000-10,000 350-2810 600 ml (1 pint)
5 Practically
5000-15,000 10,000-100,000 2820-22,590 1 litre (or 1 quart)
6 Relatively Harmless 15,000 or more 100,000 22,600 or more 1 litre (or 1 quart)
All grades of Rodrepel™ fall under the category 6 i.e. “Relatively Harmless”.
Anti-rodent additives