A long time ago I wrote a scene in a mystery with an attempted suicide by peanut butter & jelly sandwich. The character (a talented photographer with a depressing history—including a kidnapping and childhood sexual abuse) tries to kill herself in detention at New York’s famous Riker’s Island by eating a sandwich she knows will put her into anaphylactic shock. One of her other allergies—to latex—was one of the clues leading the cops to arrest her for a murder she did not commit and she is despondent at being arrested.
As I read mysteries and watch mystery TV shows & films, I gather information on murderous means. As my fellow Agatha Christie fans will attest, poison is an effective means of dispatching victims, but finding one that won’t be traced during a routine autopsy is a challenge. Murderous overdoses of medications the victim already takes, is often a good bet and it turns up in fiction all the time. The biggies are insulin and digitalis. They are common drugs—as common as diabetes and heart disease—and there are many ways to make sure a victim gets too much of a good thing.
Still ‘death by peanut butter’ and other extreme allergic reactions, never seem to go out of style in fiction. Last week I watched ‘The Escape Artist’ with David Tennant on PBS (Yes, one of the best Doctor Who actors) as a slippery defense attorney with a talent for manipulating the system. Spoiler alert! * (Skip the next sentence if you don’t want to know about the escape in ‘The Escape Artist.’) When the tables are turned on him, he makes use of an allergy to shellfish in a spectacular revenge scenario.
When using allergens as poisons, writers should be aware of the period of time as well as interactions between medications and food. For example, early anti-psychotic medications didn’t mix well with cheese. The current drugs don’t have that dietary restriction, although many meds interact badly with grapefruit.
Gluten—the current dietary devil—is not an effective means of murder. I know a few people that suffer from gluten intolerance or the rare celiac disease—but death by bread? It’s only viable if it’s spread with peanut butter.