Accidentally swallowing a plum stone, often called the pit or seed, causes immediate concern about potential harm. The pit is a hard, protective casing designed to resist the digestive process. While generally harmless for a healthy adult, anxiety stems from two primary worries: the physical risk of blockage and the chemical risk of toxicity. Understanding the digestive system and the pit’s chemistry clarifies why swallowing one is usually not cause for alarm.
The Journey Through the Digestive System
A whole plum pit descends the esophagus and, for most adults, passes easily into the stomach. The hard, dense outer shell is resistant to the strong acids and enzymes present in the stomach and small intestine. This means the seed is not broken down or digested by the human body.
Once in the gastrointestinal tract, the pit is treated like any other indigestible foreign object. It is moved through the small and large intestines via peristalsis, the muscular contractions of the intestinal walls. Transit time typically takes between 24 and 72 hours, though it can sometimes take up to five days to be fully excreted.
The physical passage is usually uneventful, but there is a rare risk of the pit causing an intestinal obstruction. This risk is higher in individuals with pre-existing gastrointestinal conditions, such as narrowed segments or hernias. For a child, the relative size of the pit means the initial risk of choking is slightly greater.
Understanding the Chemical Danger
The primary chemical concern relates to amygdalin, a cyanogenic glycoside found within the seed kernel inside the hard shell. Amygdalin itself is not toxic, but it possesses the potential to be metabolized into hydrogen cyanide (HCN) if the cellular structure is broken. This conversion process requires specific enzymes and conditions that are not met when a pit is swallowed whole.
The hard, intact shell acts as a protective barrier, preventing the amygdalin inside the seed kernel from coming into contact with the necessary enzymes and gut flora. If the pit were chewed or crushed before swallowing, the amygdalin would be released and hydrolyzed by enzymes present in the seed and the small intestine. This enzymatic reaction ultimately generates hydrogen cyanide, a fast-acting poison.
Since the pit is swallowed whole and its shell remains undamaged, the amygdalin is safely contained and passes through the system without chemical alteration. The amount of amygdalin in a single plum seed is too small to cause acute toxicity in an adult, even if the shell were slightly cracked. Fatal doses of hydrogen cyanide require the ingestion of numerous crushed or processed seeds, not a single intact pit.
When Medical Attention is Necessary
While swallowing a whole plum pit is generally safe, certain symptoms warrant immediate medical evaluation, as they can indicate a rare complication. Persistent, severe abdominal pain, especially if localized, can signal a gastrointestinal blockage. This pain may be accompanied by nausea, vomiting, or an inability to pass gas, suggesting the pit is lodged in the intestine.
Medical attention is necessary if the individual exhibits signs of acute cyanide poisoning, which only occurs if the pit was thoroughly crushed. Symptoms include sudden, rapid breathing, lightheadedness, dizziness, confusion, or cyanosis (a bluish tint to the skin). If an intact pit was swallowed, monitor the individual for a few days to ensure it passes, but address any concerning symptoms immediately.