Iron based snail and slug pellets appear to offer a safer alternative to killing snails and slugs than the traditional metaldehyde (green) and methiocarb (blue) pellets.  The active ingredient, iron phosphate or iron EDTA complex (depending on the brand) interferes with calcium metabolism in the gut of slugs and snails, causing them to stop eating almost immediately, and to eventually die within three to six days.

The pellets are water resistant and, as Iron is a common element found in soil, do not pose a risk to the soil when they eventually break down. These pellets are non toxic to mammals, birds, fish and a host of smaller organisms, including earthworms. Slugs and snails appear to be the only animals sensitive to them.

The main drawback with iron based pellets is that they are more expensive and, in my opinion, less effective than regular pellets.  But if you combine the use of them with some of the other defensive measures detailed in the DETER and DEFEND sections on this website then you should not have to use these pellets in large amounts.

They  also seem to break down more quickly than standard pellets, especially once they are wet.

The two brands of iron based pellets that I have used are :

Produced by Multicrop it's active ingredient is iron EDTA and it is readily available at most hardware stores.  But for some inexplicable reason Multicrop have chosen to offer it in a packet that looks remarkably like standard snail and slug pellet packets, so unless you are specifically looking for it you might miss it.

Made by Amgrow it uses iron phosphate as it's active ingredient.  This was the first iron based pellet I ever bought, but since then I have not been able to find in in Ballarat stores.  However it has a distinctive packet and bold name, so if it is in stores in your area than you should be able to spot it fairly easily.