Many common fruit seeds and pits contain compounds that release cyanide during digestion. The biggest sources are bitter apricot kernels, cherry pits, peach pits, plum pits, apple seeds, pear seeds, and bitter almonds. Outside of fruit, cassava root and flaxseeds also contain cyanide-releasing compounds. The risk from any of these depends on the amount consumed, whether the seed is chewed or swallowed whole, and how it’s been processed.
How Seeds Produce Cyanide
These seeds don’t contain cyanide directly. They contain a compound called amygdalin, which is a sugar molecule bonded to a cyanide group. When you chew or crush the seed, amygdalin comes into contact with enzymes in the seed itself and in your small intestine. Those enzymes break amygdalin apart, releasing hydrogen cyanide as a byproduct. If you swallow a seed whole without chewing, the hard outer coating typically passes through your digestive system intact, and little to no cyanide is released.
Which Seeds Have the Most Cyanide
Not all cyanide-containing seeds are equally dangerous. The concentration varies enormously. Bitter apricot kernels are the most potent common source, containing roughly 3,250 mg of total cyanide per kilogram. For comparison, here’s how other sources stack up:
- Bitter apricot kernels: ~3,250 mg/kg
- Apple seeds: ~690 mg/kg (with amygdalin levels ranging from 1 to 4 mg per gram depending on variety)
- Flaxseeds (linseed): ~220 mg/kg
- Fresh cassava root: 76–150 mg/kg
Cherry pits, peach pits, and plum pits fall in the same family as apricot kernels and contain similar compounds, though concentrations vary by species. Bitter almonds are also a significant source. As few as 5 to 10 bitter almonds could poison a child, and roughly 50 could be lethal for an adult.
Apricot Kernels: The Highest Risk
Apricot kernels get special attention because they’re actively marketed as health supplements and snacks, which means people sometimes eat them in large quantities on purpose. The FDA has issued warnings about products containing bitter apricot kernels, noting that they contain high levels of amygdalin that could lead to fatal cyanide toxicity. The European Food Safety Authority estimates that an adult should consume no more than three small apricot kernels (about 370 mg) in a single sitting. For toddlers, even half of one small kernel could exceed safe limits. Eating less than half of one large kernel could already push an adult past the safe threshold for a single exposure.
A crossover study in healthy adults found that cyanide from bitter apricot kernels hits the bloodstream fast, peaking about 20 minutes after consumption. The cyanide in apricot kernels is essentially as bioavailable as free cyanide because chewing thoroughly breaks down the seed tissue and activates the enzymes that release it.
Apple Seeds: Lower Risk Than You’d Think
Apple seeds contain amygdalin, but the practical risk is low. Each seed is small, and you’d need to chew and swallow a large number to reach a dangerous dose. The average fatal dose of ingested cyanide is about 1.5 mg per kilogram of body weight, so a 70 kg (154 lb) adult would need over 100 mg of hydrogen cyanide. Given that apple seeds contain roughly 690 mg of cyanide potential per kilogram of seed, you’d need to thoroughly chew a very large quantity of seeds in one sitting. Accidentally swallowing a few apple seeds whole poses essentially no risk, since the intact seed coat prevents cyanide release.
Cassava and Flaxseeds
Cassava is a dietary staple for hundreds of millions of people in tropical regions. Raw cassava root contains 76 to 150 mg/kg of cyanide compounds, and the cyanide it releases is highly bioavailable, peaking in the blood about 37 minutes after eating. This is why cassava is always processed before consumption. Traditional preparation methods like soaking, boiling, fermenting, and drying are all effective at reducing cyanide content.
Flaxseeds contain about 220 mg/kg of cyanide compounds, which is higher than cassava. However, a study measuring blood cyanide levels found that flaxseeds released cyanide more slowly and at lower peak concentrations than either apricot kernels or cassava. The typical serving size of flaxseeds (a tablespoon or two) keeps exposure well within safe range for most people.
Symptoms of Cyanide Poisoning
Small amounts of cyanide from seeds typically cause mild symptoms: headache, dizziness, mild confusion, nausea, vomiting, and abdominal cramps. Your body can detoxify small quantities of cyanide relatively quickly, so these symptoms often resolve on their own.
Large doses are a different story. Severe poisoning causes difficulty breathing, dangerously low blood pressure, irregular heartbeat, seizures, and coma. These effects can cause irreversible damage or death within minutes of symptom onset. Chronic exposure to lower levels, such as regularly eating foods high in cyanogenic compounds without proper preparation, can cause long-term nerve damage including impaired vision, hearing loss, and problems with balance and coordination.
How Cooking and Processing Reduce Cyanide
Heat and water are the two most effective tools for breaking down cyanide compounds in food. Boiling cassava for 25 minutes reduces its cyanogenic content by 45 to 50%. Boiling bamboo shoots for 20 minutes removes up to 87% of their cyanide compounds. Steaming cassava flour reduces cyanide by about 73%, and adding fermentation after steaming pushes the total reduction to over 81%.
Drying is also highly effective. Oven-drying ground material at 60°C for 8 hours eliminated 95% of cyanide content in one study. Microwave heating has shown promise too: treating plum kernels with microwaves and a hydrothermal soak removed over 98% of cyanogenic compounds, and microwaving flaxseeds at standard power for 12 minutes removed about 71%.
The key takeaway is that traditional food preparation exists for a reason. Cultures that rely on cassava, bamboo shoots, and other cyanide-containing staples developed soaking, fermenting, boiling, and drying techniques specifically to make these foods safe. Eating raw, unprocessed versions of these foods carries real risk.
What Actually Matters for Safety
Three factors determine whether cyanide-containing seeds are dangerous: the concentration of amygdalin in the seed, whether the seed is physically broken open, and how much you eat. Swallowing a few whole apple seeds or cherry pits by accident is not a concern. Deliberately chewing large quantities of bitter apricot kernels, or eating raw cassava, is genuinely dangerous.
The seeds that pose the greatest real-world risk are bitter apricot kernels (because people intentionally eat them in supplement form), bitter almonds (because of their high concentration), and improperly prepared cassava (because of its role as a dietary staple in regions where processing methods may vary). For common fruits like apples, pears, and cherries, the amount of cyanide in a few accidentally consumed seeds is far below any toxic threshold.