Q and A: Lily of the Valley Poisoning

Q: In my novel an 82 year old woman is found dead. Lily of the Valley, ground up and put in her loose tea, is what I’m using as a poison. How much should the dosage be and how will the ME find it?

B. Giersch

A: Lilly of the Valley (Convallaria majalias) is native to Canada and the Mid-West and Western US. All parts of the plane are toxic, particularly the leaves. Water in which the cut flowers have been kept is also toxic. Though the water may yield enough toxin to be deadly, a “tea” made by boiling the leaves, would certainly contain even more of the toxin and would be a more effective poison.

LILY OF THE VALLEY

The toxin in Lilly of the Valley is called convallatoxin. It is a glycoside in the same family as digitalis, which comes from the Foxglove (Digitalis purpurea or D. lanata).

FOXGLOVE

 

How many leaves would your killer have to crumble and mix with the tea? There is no way to tell. Each plant contains a different amount of the toxin so the leaves would vary greatly in their potency. The actual amount of toxin in a teaspoon of crumbled leaves is guess work at best. This is good since you can add almost any amount and be OK. Or simply skip theamountand let the reader assume the killer added enough.

Symptoms onset quickly and include nausea, vomiting, abdominal pain, flushing, hot flashes, dilated (enlarged) pupils, a red skin rash, excessive salivation, coma, and death. These glycosides can also cause deadly alterations in cardiac rhythm, which can lead to sudden collapse and death.

A toxicological examination of the blood, urine, and stomach contents would easily uncover the toxin since glycosides are easily identified. Initially the toxicologist might only be able to say that the blood contained a glycoside but not which one. Digitalis? Convallatoxin? Further testing with gas chromatography and mass spectroscopy (GC/MS) would determine which glycoside was present and would expose the actual cause of death.