SLUG PELLETS....everybody knows what they see them in their gardens looking after their Hostas' sprinkling slug pellets about like they were sowing seed.....bad habit, Slug pellets contain a chemical called METALDEHYDE, and it isn't nice. I can tell you from personal experience that they taste quite sweet, so that is a good starter for the grand children when they are roaming about in the garden. "Hey look here, granny has dropped some bluey-green sweeties in the garden, do you want one?"....OOOPS. Perhaps when you read below you might be more careful about when and how slug pellets are used. There are green alternatives on the market, just type "green slug control" into Google and it will find the site for you.


Chemical Name (IUPAC): r-2, c-4, c-6, c-8-tetramethyl-1,3,5,7-tetroxocane or more usually as metacetaldehyde

CAS No: 108-62-3. (the homopolymer is 9002-91-9).

Trade and Other Names: Some trade names include Antimilace, Antimitace, Ariotox, Cekumeta, Deadline, Halizan, Limatox, Meta, Metason, Namekil, Ortho Metaldehyde 4% Bait, Slug Death, Slug Pellets, Slug-Tox and Slugit Pellets. Mini-Slug Pellets. Some of the above names are USA trade names, so don't you UK types go lookin fer 'em....yihaaa.

Chemical Formula: C8H16O4

Chemical Structure:


  • Acute toxicity: Metaldehyde is slightly to moderately toxic by ingestion, with reported oral LD50 values of 227 to 690 mg/kg in rats, 207 mg/kg in cats, 100 to 1000 mg/kg in dogs, 200 mg/kg in mice, 175 to 700 mg/kg in guinea pigs, and 290 to 1250 mg/kg in rabbits. A child died after ingesting 3000 mg (approximately 75 to 100 mg/kg for a 30 to 40 kg child) of metaldehyde. Via the dermal route, it is also moderately toxic. The dermal LD50 for this molluscicide in rats is from 2275 mg/kg to greater than 5000 mg/kg. Metaldehyde is moderately toxic by inhalation; the 4-hour inhalation LC50 in rats is 0.2 mg/L, and the 2-hour inhalation LC50 in mice is 0.35 mg/L. Irritation of the skin, eye, and mucous membranes of the upper airways and gastrointestinal tract may result from contact with metaldehyde. Within a few hours of accidental or intentional ingestion, the following symptoms appeared in humans: severe abdominal pain, nausea, vomiting, diarrhea, fever, convulsions, coma, and persistent memory loss. Other symptoms of high acute exposure include increased heart rate, panting, asthma attack, depression, drowsiness, high blood pressure, inability to control the release of urine and feces, incoordination, muscle tremors, sweating, excessive salivation, tearing, cyanosis, acidosis, stupor, and unconsciousness and eventual death in extreme cases. Kidney injury and liver cell death ('necrosis') may also occur. Mental deficiencies and memory loss from ingestion poisoning may persist for 1 year or more. It is thought that the formation of acetaldehyde in the gastrointestinal tract is responsible for the narcotic effects observed with metaldehyde exposure.
  • Chronic toxicity: Dosages which are not toxic when given singly do not cause illness when repeated. Long-term, repeated skin exposure to metaldehyde may result in dermatitis (skin inflammation) in humans. Prolonged eye exposure can cause conjunctivitis. In 2-year toxicity studies and three-generation reproductive studies in rats, changes in liver enzyme activity and increased liver and ovary weight at dietary doses of about 12.5 mg/kg/day were found; 50% of female rats given this dose showed paralysis. Effects on the brain (e.g., impairment of memory) may also be possible with chronic exposure at very high levels.
  • Reproductive effects: During a three-generation study of rats exposed to chronic ingestion of metaldehyde, adverse effects were seen on reproduction and on the survival rate of offspring. Doses of 50 and 250 mg/kg/day interfered with the reproduction of female rats in another three-generation test. These data suggest that metaldehyde is likely to cause reproductive effects only at high levels. However, the World Health Organisation says; A three generation reproduction study with Wistar rats receiving, 1000 or 5000 mg/kg diet demonstrated an adverse effect on reproduction. Hind-limb paralysis and mortality were observed in females of all generations (including parental) receiving 5000 mg/kg diet. A low incidence of hind-limb paralysis was observed in the females of the F1 and F2 generations at 1000 mg/kg diet. Fertility, viability and lactation indices were reduced in all generations at the top dose. The onset of maternal hind-limb paralysis at or about delivery had an adverse effect on the latter two parameters. Increased relative liver weights were observed in some offspring.
  • Teratogenic effects: Dietary doses of 10, 50, and 250 mg/kg of metaldehyde were not teratogenic in three generations of experimental female rats. There were some increases in relative liver weights in some offspring. This evidence suggests that metaldehyde is unlikely to cause teratogenic effects.
  • Mutagenic effects: Metaldehyde has been reported to be a suspected mutagen. However, there was no evidence of mutagenicity when metaldehyde was tested on five strains of bacteria. The evidence regarding mutagenicity of metaldehyde is inconclusive.

Dangerous doses in Humans:

The following relationships between clinical effects and ingested dose have been suggested: salivation, facial flushing, fever, abdominal cramps, nausea, and vomiting from a "few" mg/kg; drowsiness, tachycardia, spasms, irritability, salivation, abdominal cramps, facial flushing, and nausea from up to 50 mg/kg; ataxia and increased muscle tone from 50-100 mg/kg, convulsions, tremor, and hyperreflexia from 100-200 mg/kg; and coma and death from about 400 mg/kg.

Reported mishaps:

Several incidents of metaldehyde exposure are reported in literature. Ingestion of slug-bait pellets by children accounts for the majority of the incidents reported in the United States of America between 1966-1980. In Europe, human poisonings are also associated with voluntary ingestion of tablets intended for use as fuel. Appearance of symptoms might be delayed a few hours after ingestion. Survivors of severe poisoning showed loss of memory which lasted for up to a year. Laboratory findings included acid urine despite alkali therapy and elevated serum transaminase activities. At autopsy, the main findings were fatty degeneration with zonal necrosis of the liver and swelling and desquamation of the renal tubular epithelium.

Ecological Effects:

Environmental Fate: