Be careful what you eat, especially if you're not sure if you might be allergic to a particular food.
One of the most common allergies is to peanuts. The most severe response is anaphylactic shock which if not treated immediately can be fatal. It can cause a constriction of the airways, shock, and a loss of consciousness.
Almonds, too, are more dangerous than they would appear. While in their raw form, they contain the poison cyanide. They need to go through a specialised heat treatment in order to remove the toxins.
Also watch out for stone fruit seeds and apple seeds which contain amygdalin, a compound that produces cyanide. Large doses can lead to dizziness and vomiting, increased blood pressure, kidney failure, coma, and even death. Also, avoid cherry seeds which contain poisonous hydrogen cyanide.
Raw meat and uncooked eggs may contain salmonella bacteria. Salmonella can cause gastroenteritis and also lead to serious complications, such as bacteremia (when salmonella enters the bloodstream), that are life-threatening to people with weaker immune systems.
Mushrooms can also prove fatal. So be particularly careful if you go foraging. Cremini mushrooms, for example, can contain poisons that can kill.
One of the most common allergies is to shellfish like oysters and mussels. A severe allergic reaction to shellfish can inhibit breathing and even be life threatening.
Perhaps the most famous deadly meal is the Fugu, or Puffer Fish. It may be a delicacy in Japan, but its skin and certain organs contain an extremely poisonous toxin that can paralyse a human and even cause death.