The list I have compiled here is not just a list of the top 10 most toxic substances known to man. That would be too easy and not really relevant to anyone. This list is all those deadly poisons that have, over the years, been used by humans to kill each other; either individually or en masse. Arsenic is one of the classics.
https://www.planetdeadly.com/human/deadliest-poisons-man
In mathematical terms (and I'm not saying that you have to do this) you have to check how much poison is needed to kill a mouse. A mouse weighs 19g in average. If 3g of poison are needed to kill it (I'm guessing here), you can cross multiply it: 19g -------- 3g.
https://www.quora.com/How-much-rat-poison-is-needed-to-kill-a-human
There is no type of rat poison considered dog safe.. Most rodenticides have a grain and/or sugar base, making them palatable to rodents as well as dogs. They often come in pellets, blocks, granules or liquids. They may be any color but are commonly teal, blue, green or pink.
https://www.thespruce.com/rat-poison-and-dogs-1118528
The prognosis depends on the type of chemical in the rat poison, the amount eaten and the time that has passed since ingestion. Unfortunately, the prognosis is usually poor if the dog is already showing advanced signs of toxicity. Remember, time is of the essence after a dog has eaten rat poison.
https://www.thespruce.com/rat-poison-and-dogs-1118528
Story at-a-glance 1  -. There’s a new toxin being used by rodenticide (rat poison) manufacturers for which there is no diagnostic test, nor an antidote. 2  The toxin is called bromethalin, and since 2011 it has been increasingly replacing anticoagulants (blood thinners) in rodenticides.
http://healthypets.mercola.com/sites/healthypets/archive/2013/05/24/bromethalin.aspx
Story at-a-glance 1  -. There’s a new toxin being used by rodenticide (rat poison) manufacturers for which there is no diagnostic test, nor an antidote. If your pet happens to ingest a product containing this substance, it can’t be easily detected in his system, and there’s no specific remedy to treat it.
http://healthypets.mercola.com/sites/healthypets/archive/2013/05/24/bromethalin.aspx
Cyanide is one of the best known of all poisons. Perhaps best known as the suicide pills reputedly carried by secret agents it was also the active ingredient in the gas (Zyklon B) used by the Nazis in extermination camps such as Auschwitz.
https://www.planetdeadly.com/human/deadliest-poisons-man
A case of bromadiolone poisoning in a 40-year old female who, by history, ingested four 42.5-gram bags of rat poison (0.005% bromadiolone), equivalent to 8.5 mg bromadiolone (0.17 mg/kg body weight), four days prior to admission /was reported/.
https://www.quora.com/How-much-rat-poison-is-needed-to-kill-a-human
It has been reported that 6.667 mg/kg is the lethal oral dose [Yakkyoku 1977] [Note: This is equivalent to a worker being exposed to about 300 mg/m3 for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.].
https://www.quora.com/How-much-rat-poison-is-needed-to-kill-a-human
Depending on how much poison has been ingested, symptoms can include unsteadiness, weakness, muscle tremors, paddling motions of the limbs, hyperexcitability, depression, vomiting, high fever, stiffness in the front legs, and seizures.
http://healthypets.mercola.com/sites/healthypets/archive/2013/05/24/bromethalin.aspx
how much rat poison is lethal
6.667 milligrams per kilogram of rat poison is lethal.   6.667 mg per kg rat poison is lethal.