All that is sweet is not good and all that is sour is not mean. An old quote I dont know the origin of but I like it for it says about wild fruits, from the acrid but edible rowan to the mild tasting snowberry. To produce poisoning the metabolism of the plant has to produce enough of a compound to react with the metabolism of a person. A dosage that can kill a small child may leave an adult unwell but in no danger. Toxicology is founded on the principle that dosage is the most important factor, for example both apples and choke cherries contain cyanide compounds, but obviously choke cherries contain considerably more. But even then they can processed until safe.
The following list covers the basic wild plants that can found in Western Europe. I have eaten some of these plants without ill effect, and would regard them as edible in normal quanties, but some are undoubtly very poisonous. I have tried to give some idea of how toxic each fruit is but in some cases I havent been able to find reliable or clear information. I not entirely satisfied with the information below as it can very difficult assess to how much of natural substance has to be eaten before poisoning occurs and it is common to encounter contradictory information.
Deadly nightshade
Atropa belladonna
Saccharine sweet black fruit which is becoming progressive rare. It has been confused with bilberry and produced poisoning as a result. The plant contains a complex mix of chemicals that produce poisoning notably atropine scopolamine and hyoscyamine. The first symptoms are nausea and dry mouth followed more pronounced gastric symptoms and hallucinations, coma and heart disturbance leading to death then follows.
There is an antidote and atropine toxicology is well understood by the medical profession. However the some of the toxins such as scopolamine mentally incapacitate to such an extent that medical attention is not sort, and exacerbating the poisoning.
An interesting point from a bushcraft prospective is that rabbits can eat deadly nightshade without ill effect, but it does however mean the meat can become poisonous. I cant find any cases of actual poisoning from eating belladonna bunnies though.
Woody nightshade
Solanum dulcamara
The plant has tobacco scented fruit that becomes sweeter when mature. Most of the symptoms of poisoning are gastric, but if eaten in a moderate quantity (20+fruits) other symptoms such as breathing distress and death may occur.
Black nightshade
Solanum nigrum
Causes foetal malformations in hamsters, berries are the least toxic part the plant. The less ripe the fruit is more toxic it is, the ripe fruit may be eaten without ill effects but is more likely to cause vomiting and abdominal pain. Main body of the plant and unripe fruit cause coma and death.
All solanaceous plants (potato, nightshades, henbane) are safe to handle, in fact it is one of the best ways of identifying the group is to crush the leaves and smell. If the smell can learned then the whole group can be avoided. But it does make me wonder how tomatoes or cape gooseberries were discovered to edible.
Yew
Taxus baccata
The whole tree except the fleshy fruit is poisonous. The fruit may be eaten as long as the seed is spat out. The seed is more toxic if chewed. A stick has caused lethal poisoning in a dog that was given it to play with by owner. Yew wood has been used for fine carving of bowl and spoons for centuries without ill effect, just dont let the dog chew them. Cats are very sensitive to yew poisoning as well.
White bryony
bryonia dioica
Whole plant including fruit is a drastic purgative. Old herbal remedy, the berries were called tetter berries due to the practice of removing cankers and blemishes with the fresh crushed fruit. Toxic in very small does Part of cucumber family
Black bryony
Tamus communis
Unrelated to the above plant, black bryony is also a drastic purgative as well as producing blistering of the mouth. Part of the yam family, it produces a large root. Toxic in very small doses, most of the known toxins can be treated out of the root, but it will still remain suspect until more is known about the biochemistry.
Buckthorn
Rhamnus cartharica
Violent purgative. The whole plant especially the berries and the bark are toxic in very small quanties. Small amounts (less than 10 fruits) can produce vomiting and diarrhoea, larger quanties produce haemorrhagic gastrointestinal symptoms followed by fluid loss and kidney failure. It was used as a purgative in the past, has now been replaced by safer compounds. Some populations are more resistant to its effects than others and have retained its medical use. This plant is no relation to sea buckthorn.
Alder buckthorn
Frangula alnus
Similar effects to buckthorn but less drastic.
Snowberry
Symphoricarpos rivularis
A tasteless white fruit can serious gastroenteritis even in small doses. Larger doses can produce delirium and coma. Native in north America is commonly planted in parks as hedging.
Holly Ilex aquifolium
The berries if eaten in a moderate amount produce vomiting and diarrhoea. The dried berries are supposedly a cure of diarrhoea.
Cuckoo pint
Arum maculatum
Distinctive plant with acrid juice in all parts of plant including berries. All part of the fresh plant produce blistering of the mouth and gastric problems in small doses. The root can be processed into starch by baking root then followed by cold water leechi
Ivy Hedera helix
Repulsive tasting berries have been used as a purgative in the past. Moderately small quanties will produce vomiting. The sap of the plant can cause dermatitis, which can be severe in some. The long stems makes very flexible withies and leaves were once used as cure for drunkenness.
Rose family
This family includes many common fruit trees, apple, plums, apricot, almond and sloe. The seeds of this family and leaves of some contain cyanogenic glycosides. These are cyanide chemically bounded to a sugar which breaks down when exposed to certain digestive enzymes or the leaves are crushed. In humans the acidic stomach environment can inhibit the cyanide from been released, the act of acids on the breakdown of the glycosides is also how fruit like choke cherry can rendered harmless with correct preparation.
Hydrocyanic acid and related compounds inhibit the bodys oxygen absorption and poisoning kills by causing oxygen depravation. There is an antidote but treatment must be started promptly. In Britain we are quite lucky as our indigenous prunus species are very mild. Parkland however can contain
cherry laurel and North American species which contain very high level of prunasin.
Elder
The toxicology of black fruited native elder is disputed. It has been known to cause nausea and vomiting if eaten in large quanty. Fresh fruit contains cyanogenic glycosides, but I can find no references to serious poisoning due to this in humans. Large consumption of elder berry wine can produce migraine in individuals sensitive to red wine. Non-indigenous
Red fruited elder is classified as poisonous.
Guelder rose
Not toxic as such, and has been consumed in the past, but the smell of fruit in winter can produce nausea. Other related plants such as wayfaring tree and danewort arent regarded as toxic either.
Mistletoe
Moderate consumption of the fruit can cause gastroenteritis, most poison reports involve children under the age of five. There are very differing reported negative effects from the repeated consumption. Used in variety herbal remedies, is currently been investigated as cancer treatment. Has potential to be valuable medicinal plant.
Privet
Privet fruit can cause vomiting and diarrhoea when berries are eaten in moderation.
Mezereon
Acrid tasting fruit that causes burning of the mouth when intially eaten so large amounts are seldom consumed. Various gastric symptoms then follow these can be severe if large quanties are eaten.
Herb paris Paris quadrifolia
A woodland plant that produces poisonous berries. It causes painful gastric problems and dizzyness and headaches.
Virginia creeper
parthenocissus quinquefloia
Fruit is toxic in small quantities. Consumption causes digestive and nervous system problems which can be fatal.
Spindle tree
The fruit produces vomiting and diarrhoea when eaten in large quanties, may also cause convulsions.
