All parts of this plant have toxic qualities. They contain alkaloids which can produce psychoactive symptoms. The most problematic part, though, are the red berries as they look appealing and cases of ingestion are not uncommon. The reaction depends on how much of the plant has been eaten. Chemical substances in the yew can cause nausea and vomiting accompanied by stomach aches and headaches. If more of the plant was swallowed, it may lead to dangerously low blood pressure and irregular heartbeat. One of the general safety rules is that you should never eat any unknown fruits. Treat all of them as potentially toxic, just to be on the safe side. Special attention should be paid to small kids who play in places where yews grow. If left unattended, kids can easily pop a few poisonous berries into their mouths and it can have a tragic result.

It’s a huge plant. It can grow up to 5 metres high and it produces white umbrella‑shaped flowers which can be as wide as 1 metre. It’s also very invasive and hard to eradicate. Because of the threat it poses to humans, many countries in Europe and North America issue regular alerts during hot days to watch out for this plant and not to come any close to it if anyone happens to encounter it on a walk. Its sap contains phototoxins which in contact with human skin deactivate the skin’s natural defence system. As a result of that, skin becomes extremely sensitive to the sunlight. Exposure of skin, which has come into contact with the sap, to the sun results in burns and painful blisters which can recur for many months or years. What’s more, on hot days even coming close to the plant is dangerous, as the sap secreted by it is in the air and may just cling to the skin without a person knowing about it. Sosnowsky's hogweed is another reason for wearing long sleeves and trousers during walks in the countryside.

This majestically looking plant with beautiful purple flowers contains steroid glycosides. A subcategory of them, cardiac glycosides, are commonly used in medicine to strengthen the heart muscle. However, if not used in adequate doses, or if ingested accidentally, the plant may cause a life‑threatening condition as the heart rate slows down significantly, and can lead in most serious cases to a cardiac arrest. Although this plant is used in medicine, the consumption of any kinds of plant extracts, teas, or infusions must always be consulted with a doctor.

Because of the fact that opium, which is chronically abused, is produced from opium poppies, this once widely‑planted‑in‑gardens decorative flower is illegal to be grown in many countries, for example in the U.S.A. or Poland. The poppy seeds, which are used in some regional cuisines, do not have much opium. Research has been conducted to determine what is the dose of poppy seeds that can be safely consumed by people without the risk of any harmful effects on their health. The alkaloids, that is morphine or codeine, are found in the milky sap that appears when the plant is cut. These alkaloids are widely used to treat severe pain, but, unfortunately, are also highly addictive. The opioid dependence of a large number of patients is a problem many countries have to face these days.

Because it covers huge swathes of land often adjacent to pastures, it poses a threat mostly to horses, cattle, and sheep. It contains an alcohol called tremetol which causes trembling of muscles. As the condition progresses, the shaking can spread to the whole body. Animals become lethargic and suffer from vomiting and constipation. Quick administration of appropriate drugs improves their condition. Poisoning of humans is uncommon, but they and young animals can be affected by drinking milk from cows or other animals which have been eating goldenrod.

A very decorative plant with large, flared flowers. However, chewing them causes nausea, delirium, and difficulty breathing. Moderate symptoms include agitation and hallucinations. In more serious cases, the person who ate the flowers may experience psychosis, seizures, and end up in a coma. It’s worth knowing what you plant in your front garden, as the ingestion of this particular one may finish tragically. Jimson weed is a smaller relative of angel’s trumpet that grows wild.

Stinging nettles are the plants we all have bad memories about. Despite the fact that they have many medicinal qualities, and after processing are safe to eat, direct contact with them is far from pleasant. Stems and leaves of this plant have hair which contains irritants. Touching the plant results in a tingling sensation and sometimes in a nasty burning rash. It’s not dangerous and it usually disappears within 24 hours, but it’s definitely not an enjoyable experience, especially if one ends up in an outgrown nettle field wearing shorts. However, if someone is allergic to it, the symptoms after coming into contact with stinging nettles can be much more severe and include difficulty breathing and swelling. In such cases, medical help needs to be sought immediately.

This plant has gained its notorious reputation in the family of ivies. It’s useful to know how to distinguish it from other members of the ivy family. The similarity is that it grows low on the ground or climbs trees and buildings as a vine. Its stems have got three leaves which change colour with season, and it produces whitish flowers and berries. All parts of it are toxic and coming into direct contact with it is in most cases very unpleasant. It results in itchy rashes and blisters. It’s also known as contact dermatitis. The tricky thing is that it may appear 1 to 2 days after contact. It’s the oil that the plant contains which causes the allergic reaction in people. You must be really careful with it, as not only touching the plant can have unpleasant results. Also being exposed to smoke from burning the plant may have a similar impact on the skin.

We happen to invite danger to our households oftentimes without even realising it. Monstera deliciosa is a very ornamental and hence popular houseplant. Its beautifully shaped perforated leaves grow to be up to 50 centimetres in diameter. Although it’s safe for people, unless eaten which happens extremely rarely, cats and dogs will get severely sick if they ingest it. Contrary to common belief, animals do not always have the intuition which prevents them from eating things that may harm them. Ingestion of the monstera’s leaves will cause swelling, drooling, and vomiting. It’s the calcium oxalate crystals in the plant which are highly irritating to the mouth and stomach of our pets.

Mushrooms can be really tricky. In some countries picking and preserving them is a common end‑of‑the‑summer pastime, in others it’s forbidden. One thing has to be stated very clearly: picking mushrooms for consumption must be done only by people with huge experience and knowledge about how to differentiate between edible and inedible or poisonous types. Fly agaric seem fairly easy to recognise due to their typical red caps with white spots. However, sometimes they are less characteristic and instead of bright red, their caps can be brownish and the spots not so easy to see. It’s poisonous and has psychoactive and hallucinogenic properties. Eating it will result in vomiting, nausea, increased salivation and perspiration, and a number of other symptoms.