Ergotism in Norway. Part 1: The symptoms and their interpretation from the late Iron Age to the seventeenth century.

Ergotism is a horrendous disease with grotesque symptoms caused by ingesting specific ergot alkaloids. Mass poisoning episodes are attributable to consumption of grain - usually rye - infected with the fungus Claviceps purpurea. By focusing on possible cases of ergotism, we re-examine Norwegian history from the sagas through to the end of the seventeenth century. Our review - not intended to be exhaustive, or ex post facto to assign medical or psychiatric labels - draws attention to the very real possibility that many remarkable medical cases may have been the result of the ingestion of highly poisonous and psychoactive food substances. Where possible we highlight explanations given at the time - often rooted in religion or demonology - to explain the disease.