Dealing with toxic plants (like euphorbia peplus - what else?)

I have found no list, and the only link was broken....
I also want to discuss about tips to safely collect grass.
How can you pasture animals when you have toxic plants? Yes they can eat them, I do not rely on instinct for this!

What is toxic to rabbits and guinea pigs?

I can tell you that any little piece of unseen milkweed kills a guinea pig. I have become a detective to see this plant even when I do not look for it! Do not believe they will not eat it... they do! Rabbits too!

Other than common believe sheep are not dumb, they can actually be quite smart when it comes to plants. They do only eat toxic plants when there's nothing else. Other animals too. They live in the wild and there are plenty of toxic plants!

Angelika Maier wrote: they can actually be quite smart when it comes to plants. They do only eat toxic plants when there's nothing else.

I thought that too, but it proved wrong in practise.
Sheep / goats are big enough to not die with a few plants, but both rabbits and guinea pigs do DIE ! Even when they have plenty of food, they eat it.

And it is proven in some places with a lot of euphorbia, that milk gets toxic. Toxins accumulate in the body.
Some other plants are known also to poison cattle, and who is there to know and check out if wild animals never die from toxic plants? Animals are smart but when do not live in nature, I think we have some misconceptions.

Poisonous/ harmful plants that I know of:

Buttercups
Rhododendrons and azaleas
Hygdrangea
Foxglove
Bamboo
Jasmine
Horse chestnut
Lilac
Anemone
Eucalyptus
All alliums
All plants that grow from a bulb e.g. daffodil, crocus, tulip etc (although my GPs demolished a gladiolus bed once with no ill effect)
Deadly nightshade and henbane (also leaves of any other nightshade plant though the fruit of tomato and sweet peppers are fine)
Rhubarb
All citrus
Ferns
Horsetails
All spurges
Hemlock
Oleander
Milkweed
Lily of the valley
Yew
Cowslips
Toadflax
Euphorbia
Celandine
All bindweeds
Ivy
Privet
Elder
Holly
Bleeding heart plant
Nettles (can be fed dry but avoid fresh for obvious reasons)
Dock
Any fruit seeds which cyanide e.g. apple pips
Aconite
Poppy
Ragwort

Cautions:

Spinach, beet greens, sorrel, chard etc - they can eat them but limit intake due to oxalates
Apple - too much can cause lip blistering but they usually stop eating it before this occurs
Iceberg lettuce - very watery and can cause diarrhoea

Guinea Lynx used to have a comprehensive database but I can’t seem to locate it right now.