The previous slug pellets mentioned were 3% Metaldehyde which sends slugs and snails down laughing and salivating. So they stop out all day telling jokes, swearing, getting violent and womanising, so ending up dehydrated.
Not all blue slug pellets are happy hour stuff. Some contain Methiocarb which is an altogether different chemical. Very effective against Molluscs and also Leather Jackets. This one is a nerve poison. the critters and you may wind up twitching whilst suffocating to death.
My small Metaldehyde pellet usage does not seem to be of any detriment to my Frog population.