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Do Watermelon Seeds Contain Cyanide – Read This!

Do Watermelon Seeds Contain Cyanide – Read This!

You’re doing some food shopping and see a bag of white watermelon seeds for sale as a snack.

Didn’t you read somewhere that watermelon seeds contain cyanide?

They do, but they contain such small amounts that they will not hurt you. Black watermelon seeds are not good to eat, but for reasons other than cyanide poisoning.

Do Watermelon Seeds Contain Cyanide?

Watermelon seeds contain trace amounts of cyanide. The amount is so small that it will not poison you. Never give babies watermelon with seeds, as they have been known to choke on the seeds. Black watermelon seeds can pose a choking hazard and may hurt teeth and the digestive system.

The Amount of Cyanide in Watermelon Seeds

Watermelon seeds do contain very, very small amounts of cyanide. Research from 2015 shows that seeds contain anywhere from 0.79 to 0.01mg of cyanide – in every 100 grams of seeds.

Divide that number by 100 and a seed contains 0.079 to 0.001 mg of cyanide.

What color seeds were used is never made clear. Researchers noted that this was less cyanide than can be found in sweet potato leaves, which are edible.

You need to consume anywhere from one to three milligrams of cyanide for every kilogram you weigh.

So, if you weigh 200 pounds, you need at least 90.71 milligrams of cyanide in order to get a lethal dose.

You just cannot eat enough watermelon seeds in order to die of cyanide poisoning from them.

Why Do Foods Have Cyanide?

Many foods contain cyanide or chemicals inside that turn into cyanide when eaten.

These include not just watermelon seeds but most other kinds of seeds, including flaxseeds, apple seeds, peach pits, cherry pits and apricot pits.

Other foods that include cyanide are:

  • Cassava roots, also called yucca or tapioca
  • Almonds
  • Barley
  • Sorghum
  • Lima beans (you always suspected there was a reason you didn’t like them)
  • Bamboo shoots.

Why do these plants contain cyanide? Seeds and other parts of plants are prized food for insects. 

Cyanide acts as an insecticide. Plants make sugar that binds to a cyanide molecule.

When the insect eats that plant, the cyanide causes cells to be unable to use oxygen. The reason you die from cyanide is that you choke to death.

Cassavas are a common food in Africa. The roots have to be specially prepared before they can be turned into flour.

Unfortunately, this preparation takes time. Cassava poisoning is common, especially among the poor. It’s so common that it even has its own name, konzo.

Black Watermelon Seeds Could Be Choking Hazards

Although the white seeds in watermelon are small enough to be easily swallowed, the black seeds can be much larger. It is possible to choke on them.

This rarely happens to adults, but can happen to babies, since they have much smaller windpipes.

Never give watermelon with seeds to babies. When babies are six months old, they can have watermelon puree.

Since it’s sweet, it’s usually a hit with babies.

When they are a little older, they can start having chunks. Watermelon contains beta carotene, which the body converts into Vitamin A, an antioxidant.

Seed Bezoars

This is an extremely rare condition that probably won’t happen if you are in reasonably good health.

A bezoar is a stone-like impaction in the digestive tract. Usually, it’s made of hair or fibers from clothes.

They can also be made of pills that, for some reason, never dissolved in your stomach, or from tough plant material, like seeds.

According to the Mayo Clinic, people most at risk of getting any kind of bezoar include:

  • Anyone who has had gastric surgery
  • People who need to be on a ventilator or other breathing device
  • People with end-stage kidney disease
  • Diabetics
  • Anyone who has a smaller than normal stomach, such as when you have stomach reduction surgery
  • Anyone with a stomach that does not produce a normal amount of acid.

Pets can also get bezoars, including bezoars made of seeds.

Dogs are especially prone to bezoars since they have a tendency to swallow their food whole.

According to the American Kennel Club, dogs enjoy watermelon, but please remove the seeds and the rind before giving any to your dog.

Other Potential Problems with Watermelon Seeds

With the exception of small, white seeds, which are immature seeds, the fully mature watermelon seed is very hard.

Although people have been known to chew on them, they can hurt your teeth.

People with already sensitive or bad teeth should avoid very hard foods like watermelon seeds, ice cubes or even stale bread.

People with crowns, dental implants or bridges also need to avoid hard foods in order to avoid cracking the very expensive dental work.

One problem that will never happen if you swallow a watermelon seed is that a watermelon plant will grow in your stomach.

This is a common misconception that’s been around for about as long as people have been eating watermelons. What happens is that seeds pass through the digestive system intact.

Which can lead to another problem – aggravation of hemorrhoids or anal fissures. If you have hemorrhoids or an anal fissure, the last thing you want to do is pass a very hard object, no matter how small or thin it is. This causes flare-ups.

Frequently Asked Questions About Do Watermelon Seeds Contain Cyanide

How Many Watermelon Seeds Does It Take to Kill You?

Watermelon seeds are not poisonous, so you can eat all you want and they will not kill you. However, watermelon seeds can still kill you because they can be a choking hazard. You should never give babies watermelon with seeds, as babies have been known to choke to death on them.

What Seeds are Poisonous?

Many seeds are poisonous, but watermelon seeds are not. Common poisonous seeds that children are known to swallow are from the plants four o’clock, foxglove, lily-of-the-valley, jack-in-the-pulpit, morning glory and sweet peas.

What Seeds Contain Cyanide?

Most seeds, like watermelon seeds, contain trace amounts of cyanide. Seeds that contain enough cyanide to hurt you include cherry pits, apple and apricot. These seeds are usually harmless if swallowed whole. If these seeds are chewed enough or crushed, they can potentially poison you.


Many seeds contain tiny amounts of cyanide. Watermelon seeds contain a variable but tiny amount of cyanide.

This is not enough to hurt you. White watermelon seeds are sold as snacks.

Black watermelon seeds could kill you by being a choking hazard or by blocking your digestive tract if you eat a lot, although the latter hazard is very rare.