The highest rated mouse poison, as of January 2015, is Havoc Di-Kill pellets, according to bestcovery.com. Its number one rating was achieved due to a combination of effectiveness, safety and affordability.
Havoc Di-Kill pellets work as anticoagulants, which cause rodents to bleed internally and die. Anticoagulants are safer to use because vitamin K, which is readily available, can be used as an antidote if necessary. Also, the pellets are in a package that rodents have to gnaw through, rendering them less likely to be eaten by children or pets. Mouse poisons can also use nervous system disruptors, which kill by shutting down the nervous system. Nervous system disruptors have no known antidote and are more dangerous to use.