The Devil's Weed
Colonists arrived on the shores of Jamestown Island in 1607. At first look, this was an ideal location. No native inhabitants, prefect visibility to watch for any Spanish ships approaching. A safe, insulated place. As we all know, looks are so often deceiving.
In reality, a lack of any vegetative sustenance, no wildlife for hunting, a filthy water supply and a voracious mosquito population made the island a very poor home, indeed. It was however, overrun with a particularly attractive weed, that sported pretty, trumpetlike flowers which some of the settlers took the chance with by adding them to their food and drink.
The weed took hold of them quickly causing convulsions, hallucinations and failure of their respiratory systems resulting in death.
Seventy years later when British soldiers arrived, descendants of the original settlers remembered their history well and placed the plant into the soldier's food. They did not die, but instead went mad - for eleven days. ."..the effect of which was a very pleasant comedy, for they turned natural fools upon it for several days: one would blow up a feather in the air; another would dart straws at it with much fury; and another, stark naked, was sitting up in a corner like a monkey, grinning and making mows [grimaces] at them; a fourth would fondly kiss and paw his companions, and sneer in their faces with a countenance more antic than any in a Dutch droll.
In this frantic condition they were confined, lest they should, in their folly, destroy themselves — though it was observed that all their actions were full of innocence and good nature. Indeed, they were not very cleanly; for they would have wallowed in their own excrements, if they had not been prevented. A thousand such simple tricks they played, and after eleven days returned themselves again, not remembering anything that had passed." - The History and Present State of Virginia, 1705