Slug Pellets – Dangers and Hazards

Slug pellets should be used as a ‘last resort’, but I’m telling you about them first because they’re often the gardener’s first (and only) resort.

A little heap of metaldehyde slug pellets

Metaldehyde slug pellets

Despite their popularity, slug pellets are one of the least effective methods of slug control, killing no more than 10% of the slug population in the average garden. However, they do pose a real hazard to other wildlife, pets and even young children.

Slug pellets are based on one of two active ingredients; Metaldehyde or the less common Methiocarb.

Metaldehyde pellets

Metaldehyde is the most common and less toxic form of slug poison. Whereas methiocarb causes the slug to swell up with fluid and die, metaldehyde damages the mucus cells causing the creature to produce masses of slime and dehydrate. If not killed outright, it’s immobilised and unable to retreat to its daytime shelters. Metaldehyde also affects the slug by contact and absorption whereas methiocarb needs to be ingested.

Being less toxic, metaldehyde is not so fatal to other animals if consumed in small doses, so ALWAYS apply it thinly as directed. One pellet every 10cm (4”) is more than enough to attract a slug, without giving the friendly hedgehog a lethal dose.

Methiocarb pellets

The less common methiocarb is about ten times more poisonous than metaldehyde, thus posing far greater danger to other animals. It breaks down more slowly too, making it a longer lasting hazard. It’s also an insecticide, meaning it kills off many other insects, including the friendly slug-eating beetle and the beneficial earthworm. So all in all I really don’t see any place for these horrid methiocarb poisons in the garden shed.

Fascinating fact

Metaldehyde was originally used as a solid fuel in the form of meta-tablets. Its slug killing properties were accidentally discovered by farmers in southern France who noticed dead and dying slugs and snails on picnic sites where meta-tablets had been left on the ground.

Slug bait

I once thought the slug was a dumb creature; stupid enough to be ‘attracted’ to the poisonous pellets. However, the active chemical only makes up about 5%, with the majority consisting of other slug luring ingredients such as cereal and yeast. This gives rise to the often used term ‘slug bait’. Pure metaldehyde actually repels slugs, hence the futility of applying slug pellets too thickly.

See...  the slug isn’t so dumb after all!

Handy hint

Make your own eco-friendly slug bait from raw oats or bran, either small heaps or scattered around vulnerable plants. The greedy slug bloats itself up on it, leaving it dehydrated and easy pickings for the birds.

Pets and young children

The formulation of slug pellets is very similar to dried cat or dog food, making it particularly appetising to your beloved pets. The blue colour is meant to deter, but most have eyes bigger than their stomachs! Of all the pet poisonings seen by vets, slug pellets, especially the methiocarb type, cause the majority.

The blue colouring intended to make slug pellets unappealing to birds and animals actually makes them look fascinating to a young child. And what does a toddler do with everything it picks up? It’s straight in the mouth!

Because the active ingredient makes up less than 5%, ingesting a single pellet poses little harm to children or other animals; however, problems arise due to:

  • Improper usage – where a person scatters excessive amounts of pellets or forms little heaps. Now a child or animal can consume a more deadly dose.
  • Improper storage – where pellets are stored in easily accessible places, in inappropriate containers, or without proper refitting of child proof lids.

Improper storage is the cause of most instances of slug pellet poisonings.

Wise precaution

As with all hazardous substances, always keep slug pellets well out of reach of children, and securely sealed in their containers.

Nemaslug – nematode slug killer

Nemaslug pack

Nemaslug – Slug Killer

The environmentally friendly alternative to traditional slug pellets; Nemaslug is the perfect choice for the ecological gardener who hates using chemicals and poisons in the garden. In fact, the nematodes are already present in smaller numbers in most soils, so you aren’t introducing anything new into your garden.

Simply mix the nematodes with water and apply to the soil – job done. Up to two month's protection from a single treatment.

Don’t let slugs spoil your garden this year!

Nemaslug slug killer
Find out more


There will always be occasional emergencies when nothing else seems to work, but for the most part, isn’t it time to banish slug pellets to the top shelf of the garden shed?


Spare a thought for the wildlife...

Think about the ineffectiveness of slug pellets as a control method and the harm they can do to birds and animals, then consider the many other eco-friendly mollusc management ideas on this site.

Of course, you could always try the alternative, and far more entertaining, method of deploying those little blue pellets...  as depicted at the top of this website!

What do you want to do now

Organic Slug Killer

Nemaslug slug killer

Had enough of holey hostas and lacy lettuce?

Want to protect your plants from ravenous slugs without resorting to poisonous pellets?

Nemaslug is what you’re looking for.

Harmless to humans and wildlife; safe on food crops. Dead slugs are non-toxic to other animals.

Nemaslug slug killer
Find out more

Did you

Slugs are hermaphrodite, having both male and female reproductive organs

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