Is Your Cucumber Brown Inside? It’s Probably Belly Rot

When you’re slicing up a nice cucumber for a salad, the last thing you usually expect is to find brown spots – and this is an off-putting discovery to make. You might be wondering how these brown spots get there and whether they make the cucumber inedible.

Brown spots in a cucumber are usually caused by something known as belly rot, which is a disease that spreads through the soil and can affect the cucumber on both the outside and the inside. Old cucumbers may also naturally develop brown spots as they break down.

It’s important to check whether a cucumber is safe to eat before you tuck into it, and if the idea of belly rot doesn’t appeal to you, let’s find out a bit more about this fungus and how it affects your food.

Why Is My Cucumber Brown Inside?

cucumber in bad state

Your cucumber is likely to have turned brown due to a fungal infection known as belly rot. This is caused by a fungus called Rhizoctonia solani, and it can also be referred to as soil rot. It attacks the fruit and causes the cells in it to break down and start decomposing.

It will cause mushy brown spots on the cucumber in any area that it attacks, including in the center of the cucumber if it can get there. The fruit will start to turn slimy and squishy, and will lose all its structure and firmness. It will no longer be safe to eat, and you will need to get rid of that part of the cucumber.

Alternatively, your cucumber may have gone brown inside because it is old. This will usually show on the outside of the cucumber first, and old cucumbers tend to go limp and mushy, but in some cases, brown spots might appear inside the cucumber’s flesh too. This is more likely to happen if the skin of the cucumber has been damaged by something.

On the whole, the inside of the cucumber will be protected by the outer skin, which is tough and defends the soft flesh from decay and infections. However, if the skin gets damaged or bacteria or fungi find their way into the fruit through a small hole, the inside is just as likely to decay as the outside.

Is A Brown Cucumber Safe To Eat?

It might be a little unnerving to find brown spots on your cucumber, but you may not need to just throw it straight into your compost bucket. In some cases, brown spots can be cut out of the cucumber, leaving the rest for you to enjoy as normal.

If you want to eat a cucumber that has brown spots, look at the following:

  • How large are the brown spots?
  • How dark are the brown spots?
  • Is the flesh around the spots firm, or has it also turned mushy?
  • How old is the cucumber?
  • How long ago did you cut the cucumber open?
  • What does the cucumber smell like?

All of these things will help you to determine whether the cucumber is still safe for you to eat, or whether it needs to be discarded. If the spots are large, very dark, and surrounded by mushy flesh, the cucumber probably needs to be thrown away, especially if you cut it open some time ago and it has been in the fridge for a while.

If you are unsure, cut off the section of the cucumber that contains the brown spots, and see how the next section looks. If it is firm and light green, that part of the cucumber is probably fine to eat, and you can just throw away the brown section.

Could Eating A Bad Cucumber Make Me Sick?

You do need to be cautious about eating cucumbers with brown spots, because you will not be cooking your cucumber, and raw food has a higher risk of containing bacteria, since these will not be killed off by any heating process.

Eating a moldy cucumber certainly could make you sick, and although vegetables tend to be less dangerous than meats in this respect, you still need to be very careful, or you could contract serious food poisoning. In some cases, food poisoning can even be bad enough to cause hospitalization, so do not take this too lightly.

If you think a cucumber is unsafe to eat, you can use your sense of smell, touch, and sight to check whether it has gone bad. Flesh that is squishy or slimy is no longer safe to eat, and flesh that has gone brown, white, green, or any other unusual color should be discarded. Equally, cucumber that has taken on an unpleasant scent is not safe to eat.

Eating a bad cucumber could potentially make you very ill, so if you ever put a slice of cucumber in your mouth and notice that it tastes odd or it has gone particularly mushy, spit it out and rinse your mouth out; do not swallow it. This should reduce the risk of consuming anything unsafe.

Will Brown Spots Spread?

If you notice brown spots on your cucumber, they are a sign that the cucumber will go off soon. The spots may not spread, but the rest of the flesh will soon start to break down too, and will become unsafe to eat.

Sometimes brown spots are localized in an area that has been damaged, and the rest of the cucumber will be fine. You can chop off any brown sections that are due to damage and put the rest of the fruit in the fridge, and it should stay green and firm for several days, provided it hasn’t also been damaged.

Don’t leave brown areas on the cucumber if you notice them; cut them away instead.


The simple answer to why is my cucumber brown inside is that it may have been damaged, or it might have been exposed to a fungal infection that causes the flesh to degrade. If your cucumber has brown spots, cut them away and inspect the rest of the flesh carefully before eating it.

Alexandre Valente

Hey there! My name is Alex and I've been vegan for more than five years! I've set up this blog because I'm really passionate about veganism and living a more eco-conscious life. Hopefully, I can use this website as a channel to help you out on your own journey!

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