Toxicity of plant material used as emergency food during famines in Finland.

The use of natural plants as emergency food in Finland and northern Europe has been described. The chemical contents of the commonly used "pettu" (pine bark), lichen (Cetraria islandica, Cladonia sp.) and water plants (Calla palustris, Menyathes trifoliata, Nymphea sp. and Nuphar luteum) are described and their toxicity after traditional pretreatments were studied in mice and rats. As 50% w/w mixture in normal food none of them were tolerated by mice. However, rats tolerated 25% of "pettu" and ash-treated C. islandica in 3-month tests rather well, although the body weight did not increase as much as in controls. At the end of experiment in the lichen group, the rats had proteinuria, and on autopsy some tubular changes were found probably due to high concentrations of lead in the lichen and kidneys. All the rhizomes studied contain toxic compounds, but they, particularly calla, would be nutritionally valuable. Boiling poorly eliminated their toxicity, but after baking at 180-200 degrees C the most toxic Nuphar and calla were well tolerated as 25% mixture during a 6-week test. It is possible that poorly selected or poorly pretreated emergency food have sometimes contributed to the death of famine victims in the olden times. Unqualified simplification of the traditional precautions for their treatment may be dangerous.