This plant Bittersweet is categorized into the family of Solanceae. If the plant still is unripe all parts offer poisonous substances.
Bittersweet grows in moist and wet areas (e.g. brookside) and due to its normal height of 30 cm it is a subshrub.
It has a distinctive outward appearance: the yellow anther and the berries hang out of the violet flowers. The plant is quite popular because its bright colors are really impressive.
The name “Bittersweet” refers to the taste of the berries: if you eat the ripe ones they taste bitter before they leave a sweat aftertaste in the mouth.
The toxicity of this plant depends on the state of ripeness.
Unripe berries (green color) offer a high dose of the toxic substance Solanu-Alkaloid but the leaves and the stem are less poisonous. In opposite to this you can even eat ripe berries (red color) but only up to a certain dose. If you eat more than 30-40 ripe berries this has toxic effects on humans. Unfortunately until today we do not know about the critical dose for horses but in case of a poisoning you need to notice the following symptoms: inflammation and irritation of the mucosa (e.g. in the mouth), colic, diarrhea, damage of the kidney, disturbance of equilibrium and a red-brown color of the urine. Despite of its toxic substances bittersweet also has homeopathic effects. Dried stems of a two years old plant are used for the cure of neurodermatitis.
In general one needs to control all places where horses are without supervision (e.g. pastures) if there are any poisonous plants.