July 9, 2025, 3:49 am | Read time: 4 minutes

Many amateur gardeners use slug pellets to prevent a slug infestation. What many don’t know is that the small blue, red, or green pellets can pose a danger to pets and children.

What Are Slug Pellets Anyway?

Slug pellets are a widely used method for combating slugs in the garden. They are spread in the form of small pellets or granules in blue, red, or green on beds or paths and attract slugs with scents and attractants. After ingestion, the animals die—depending on the active ingredient—either immediately or within a few days.
The most commonly used active ingredients are:

• Metaldehyde
• Iron-III-phosphate
• Methiocarb (banned in Germany since September 2014)

How Do Metaldehyde and Iron-III-Phosphate Affect Slugs?

• Metaldehyde is neurotoxic: When mollusks ingest the active ingredient through slug pellets, it leads to increased mucus production, muscle spasms, and eventually death by dehydration or paralysis. Death often occurs within a few hours.
• Iron-III-phosphate, on the other hand, works more slowly but more gently. It blocks calcium absorption in the slug’s digestive tract, causing it to stop eating and retreat to its hiding place, where it eventually starves. Its appetite is literally spoiled. This makes the effect less obvious to the gardener, as the slug carcasses are usually not directly visible, but it is just as effective. The big advantage: Iron-III-phosphate is specifically effective only against slugs.

How Toxic Are Slug Pellets for Pets and Children?

Danger to Pets from Slug Pellets

Metaldehyde-based slug pellets are particularly dangerous—especially for dogs, cats, hedgehogs, and other small animals. Even small amounts can lead to severe poisoning symptoms. For example, in cats, it can often be enough if they ingest a small amount, leading to severe poisoning symptoms such as excessive salivation, muscle spasms, and eventually death from dehydration or paralysis. Death often occurs within a few hours.

Iron-III-phosphate is considered significantly less dangerous. It specifically targets slugs and is largely harmless to birds, mammals, and earthworms—at least in usual dosages. However, it is still important to ensure that children or pets do not come into contact with the pellets. Store them in a shed on the top shelf or, even better, in a locked cabinet.

Why Children Are Particularly at Risk

To small children, slug pellets often look like candy—similar to sugar pearls or Smarties. Their curiosity is quickly piqued, and just a handful can cause serious health problems. If there is any suspicion that a child or pet has ingested slug pellets, a doctor or veterinarian should be consulted immediately, or the poison control center should be contacted.

More on the topic

Pests Five Common Garden Pests and Effective Ways to Combat Them

Ethical and Legal Reasons Why You Shouldn’t Use Salt to Combat Garden Snails

Control Pests Copper Tape Can Effectively Repel Snails in the Garden

Are There Natural Alternatives?

For those looking to combat slugs using non-toxic methods, consider:

• Collecting slugs early in the morning or evening.
• Slug barriers such as copper tape, slug fences, or rough strips of lava granules. Coffee grounds or mandarin peels can also deter slugs.
• Using beer traps (though be cautious: the smell that attracts slugs can also draw them from neighboring gardens).
• Encourage natural predators such as birds, frogs, and hedgehogs to inhabit your garden.

Safety Over Slug-Free Gardens

Ensuring safety is more important than having a slug-free garden. I rely on a combination of several natural methods: In addition to handpicking slugs early in the morning, mulching with dry materials like straw, sand, or lava granules has proven effective—slugs avoid dry, rough surfaces. Coffee grounds scattered around the beds also act as a deterrent while improving the soil. The garden may not be completely slug-free, but it’s safer.