Sweden has three snakes, and only one of them can hurt you. The adder is shy and bites only when you nearly step on it, but a bite is an emergency, and the current official advice is simple: call 112.
When you need this
Someone in your group has just been bitten, or thinks so. Or you’re walking a sunny island path in June with children, or a snake has settled by the steps of your rental cabin. This page covers the bite first, then how to recognize the adder, where and when it turns up, and what Swedish law says about snakes.
If someone is bitten: call 112 at once
1177, the Swedish health service’s advice site, last updated its adder page in June 2026, and the instruction is plain: call 112 at once if you suspect an adder bite. Giftinformationscentralen, the national poison center, says the same: ring 112 and ask for Giftinformation (poison information). Some older guides still tell you to call the advice line first, and some agency pages say to contact a hospital or health center. Follow 1177’s current advice.
What to do while you wait, from 1177 and the poison center:
- Call 112 and ask for poison information. The operator helps you decide whether it was an adder.
- Calm the person and let them rest, lying down if possible. Venom spreads faster with exertion.
- Keep the bitten body part still.
- Take off rings, watch, bracelets and shoes before the area swells.
- Leave the bite alone. Don’t cut, suck, squeeze, cool, heat or tie anything around the limb. It can make the venom spread faster.
- Go to hospital if told to, with someone accompanying you. If the bitten person feels ill, 112 sends an ambulance. Don’t drive yourself if you have symptoms.
Expect to stay a while. The poison center’s clinical advice to hospitals is observation for at least six to eight hours, and at least 24 hours if antivenom is given.
Children, elderly people and pregnant women are especially sensitive, according to 1177. With a child, follow the same steps, keep them resting and still, and don’t wait to see whether symptoms appear. Our guide to camping with kids covers the rest of the family outdoors.
How dangerous is an adder bite?
A bite can be anything from nothing at all to a severe reaction. Sometimes the adder injects no venom, a so-called dry bite, but nobody can tell in advance. That’s why the poison center wants everyone who is bitten observed in hospital.
| What can happen | Detail |
|---|---|
| The bite mark | Usually two small punctures 6–9 mm apart; sometimes nothing visible |
| Local reaction | Swelling at the bite, sometimes the whole limb; peaks after two to three days |
| General reaction (uncommon) | Vomiting, diarrhea, dizziness, difficulty breathing, fainting |
| Timing | Usually within minutes; exceptionally up to six hours later |
| Treatment | Observation; antivenom for strong reactions |
Deaths are very rare, and these are the official figures. Until the 1950s someone died of an adder bite almost every year in Sweden, mostly children. Since safe antivenom arrived in the 1980s, Giftinformationscentralen knows of two deaths in 45 years: one in 1994 and one in 2023. The 2023 victim did not go to hospital. Pages that say “no deaths since the 1990s” are out of date.
Bites are not rare, though. Läkemedelsverket, the medical products agency that runs the poison center, says about 400 people a year are treated in hospital after adder bites, and many need antivenom. The poison center took 678 calls about adders in 2025, against a record 1,225 in 2018.
Adder, grass snake or smooth snake?
Naturvårdsverket, the Swedish Environmental Protection Agency, puts it simply: of Sweden’s snakes, only the adder is venomous, and all the others are harmless. The trouble is telling them apart. Here’s how the county board (Länsstyrelsen) and the Swedish Museum of Natural History describe them:
| Adder (huggorm) | Grass snake (snok) | Smooth snake (hasselsnok) | |
|---|---|---|---|
| Venomous | Yes | No | No |
| Pattern | Dark zigzag band on grey or brown; some are all black | Grey or black, usually light patches behind the head | Grey-brown, two rows of dark spots that can merge |
| Eye | Vertical, cat-like pupil | Round pupil | Round pupil, dark streak through the eye |
| Head and body | Small head scales; fairly thick, short tail | Large head plates; slimmer, glossier | Large head plates; slimmer, glossier |
| Habitat hint | Sunny, stony places | Water and wetland | — |
Three traps. Black adders are locally common and have no visible zigzag, and the band can be faint or missing on others. A black grass snake may lack its light neck patches and look like a black adder. And the smooth snake is the one most often mistaken for an adder. It’s harmless and strictly protected.
A kopparödla (slow worm) is not a snake at all but a legless lizard. It’s harmless and protected too.
If you can’t tell, it doesn’t matter much: don’t touch it, walk around it, and treat any bite as an adder bite. A grass snake bite leaves rows of small tooth marks rather than two punctures, but that’s for the 112 operator to judge. Never pick up a snake. The poison center stresses that small adders are dangerous too, and that adders can swim and climb.
Where and when you meet adders
Adders live across Sweden up to about the Arctic Circle and are absent only in the far north. The Swedish Museum of Natural History says they are seen most often in the archipelagos, where voles are plentiful and predators few. They like sunny, stony ground: rock slabs, stone walls, heath and forest edges. Grass snakes prefer lakes, ponds and wetlands.
| Period | What adders are doing |
|---|---|
| Late February/March–April | Leaving winter quarters; bask sluggishly for three to four weeks |
| April–May | Mating, near the winter sites |
| June–August | Very active, especially in warm weather; the peak bite season |
| August–September | Young born, 12–23 cm long and venomous from birth |
| Autumn | Activity tails off; dogs are still bitten |
To lower the odds: wear boots or sturdy shoes on rocky, sunny ground rather than trainers. Long trousers give some protection. Look where you put your hands and feet on stone walls and rocks. Remember that an adder never attacks and bites only if you almost step on it.
Dogs and adders
Adders bite dogs every summer. The university animal hospital in Uppsala alone had recorded 78 bitten dogs by 16 July 2025, so keep your dog on the path and away from sunny stone walls in adder season.
For a dog, 112 and the poison center are the wrong numbers: the poison center doesn’t advise on animals. Keep the dog as still as possible, carry it if you can, and phone a vet at once. Don’t bandage, cool or suck the bite. Our guide to vets in Sweden explains out-of-hours cover, and dogs in nature covers the other seasonal risks.
The law: don’t kill it
Every Swedish snake is protected (fridlyst) under the Species Protection Ordinance (Artskyddsförordningen). Killing, injuring or capturing one is forbidden, and breaches are punished under the Environmental Code.
- The garden exception: an adder found on a house plot (tomtmark) may be caught and moved. It may be killed only if catching it is impossible and there is no other suitable solution. Naturvårdsverket advises moving it at least a couple of kilometers, and only if you are used to handling snakes.
- The exception covers adders only, and only on plot land. It doesn’t apply on a trail, in the forest or on a beach, and never to the smooth snake. The smooth snake has strict EU protection, which also forbids disturbing it on purpose.
- From 1 November 2026 the ordinance is restructured into protection levels. The adder and grass snake get “basic protection”, which forbids intentionally killing, injuring or capturing them. The garden exception is unchanged.
For a visitor that means one thing: if you meet an adder on a path, step around it and walk on. Killing it is an offence, and the snake may be a harmless smooth snake, the species most easily mistaken for an adder.
Practical information
| What | Detail |
|---|---|
| Emergency number | 112, free, works without a SIM — ask for Giftinformation |
| Poison center, less urgent | 010-456 67 00 |
| Hospital care after a bite | Fees set by the region where you are treated; EU/EEA and UK card holders see our EHIC and GHIC guide |
| Moving an adder from your plot | Allowed; no permit needed |
| Bitten dog | Call a vet — fees set by each clinic |
| Peak season | June–August; adders active from late February/March to autumn |
FAQ
Are there poisonous snakes in Sweden?
One: the huggorm, or common adder. Sweden has three snakes, and the grass snake and smooth snake are harmless. The adder is found across the country up to about the Arctic Circle and is most often seen on sunny, stony ground and in the archipelagos. It never attacks and bites only if you nearly step on it, but a bite needs emergency care.
What should I do if I’m bitten by an adder in Sweden?
Call 112 at once and ask for poison information. Rest, keep the bitten limb still and remove rings, watches and shoes before swelling starts. Do not cut, suck, cool, heat or tie off the bite. The operator helps decide whether it was an adder and usually sends you to hospital for observation. Don’t drive yourself if you feel ill.
Can an adder bite kill you?
Very rarely today. Until the 1950s deaths happened almost every year, mostly children. Since antivenom arrived, Giftinformationscentralen knows of two deaths in 45 years, in 1994 and 2023; the 2023 victim did not go to hospital. Still, about 400 people a year are treated in hospital, and children, elderly people and pregnant women are especially sensitive.
How do I tell an adder from a grass snake?
Look at the pattern and the head. An adder is grey or brown with a dark zigzag band and a vertical pupil, though some are all black. A grass snake usually has light patches behind its head and a round pupil. The smooth snake, grey-brown with two rows of dark spots, is the one most often mistaken for an adder.
Is it legal to kill an adder in Sweden?
Generally no. All Swedish snakes are protected, so killing, injuring or capturing them is an offence. The one exception is an adder on a house plot: you may catch and move it, and kill it only if catching it is impossible and no other solution exists. The rule does not apply on trails or in the forest, and never to the smooth snake.
When are adders most active in Sweden?
They leave winter quarters in March or April and bask, sluggish, on sunny spring days. June, July and August are the busiest months, especially in warm weather. Young are born in August and September and are venomous from birth. Watch stone walls, rocky slopes, heath and island shores on warm days.
What if my dog is bitten by an adder?
Keep the dog as still as possible, carry it if you can, and phone a vet at once — movement spreads the venom. Don’t bandage, cool or suck the bite. The poison center does not advise on animals and 112 is for people. Bites are common in summer: one animal hospital treated 78 bitten dogs by mid-July 2025.
Related guides
- Emergency numbers in Sweden — how 112 works and what to say when you call
- Camping with kids in Sweden — adders, ticks and water safety for families
- Dogs in nature — adders, ticks and leash rules for your dog
- Ticks in Sweden — the far more common outdoor bite, and how to deal with it
- Healthcare as a tourist — what hospital care costs and how to pay
Facts verified 2026-09-25. Sources: 1177 Vårdguiden, Giftinformationscentralen and Läkemedelsverket, Naturhistoriska riksmuseet, Naturvårdsverket, Länsstyrelsen Kalmar, Sveriges riksdag (Artskyddsförordningen), SOS Alarm — full register in this topic’s source file. Found something outdated? Tell us and we’ll fix it.