Lupin is a type of flowering plant of the genus Lupinus. Some of these plants are posisonous to both people and animals. The lupin plant is also called bluebonnet and is sometimes spelt lupin.
The culprit behind the plant's toxicity is lupinine, which is an alkaloid. It makes the plant taste bitter. Some lupins are called "sweet lupins," but these, too, can be toxic.
As a bean plant, some lupin is eaten. Some beans are consumed by humans while some lupin is grown for livestock. Unfortunately, it is hard to know the edible from the inedible.
All parts of the plant are toxic, the seeds and pods especially, since the lupinine toxic is concentrated there. Dried lupin is also toxic.
Depending on the time of year, environment and the stage of growth the plant is in, lupin varies in its toxicity. Thus, what may have been edible during one season might have become toxic at another time.
Lupin poisoning causes heart problems, nervousness, digestive problems and cognitive problems, among other symptoms.