It may surprise you that cactus spines are not poisonous. They’re meant to keep animals away from the succulent itself, but they rely entirely on the pain of the poke rather than any poison or venom in the spines to keep themselves from being eaten.
Cactus spines are sharp and pointy in an attempt to herbivores like camels at bay, so they don’t eat cactuses! Even when the cactus itself is poisonous, the spines of the cactus still aren’t poisonous. This doesn’t mean they aren’t still dangerous, though.

Cactus spines are typically not poisonous.
When most people think of a cactus, they picture a spiky desert plant. This type of cactus can be small enough to fit in your palm or tall enough to tower over you. While these plants are well-known for their spines, which would cause pain if you touched them, they aren’t known for being poisonous. However, this doesn’t mean that cacti are completely harmless.
Most of the time, if you touch a cactus with one of its spines and feel pain, it’s because the spine is sharp and has punctured your skin. You’ll hurt for some time after removing the spine because it leaves a lot of tiny cuts from the barbs on the spines going in and out. This isn’t dangerous when it comes to poisoning or toxins from the plant itself. The spine is made from lignin—the same substance that help form the cell walls of plants. Cactus spines are essentially modified leaves that were redesigned to hurt you instead of collecting sun for the plant.
However, getting pricked by a cactus could be dangerous at times because there may be bacteria on the spine or in its tissue that can lead to infection if left untreated. It also might cause an allergic reaction in people who have allergies to certain plants or chemicals found within them.
Cactus spines are designed to keep animals from eating the cactus.
Cactus spines are there to protect the plant from hungry animals. As we can see, cacti have had to evolve to survive without being eaten. Cacti evolved in desert regions, where water was scarce and hard to come by.
If their fleshy parts were eaten by animals, they would not be able to grow fully. They would die before they could reproduce and spread their seeds.
The spines of cacti are actually modified leaves or branches whose ends are sharpened and hardened into fine points that resemble needles.
The number of spines a cactus has varies depending on the species of cactus it is. Some of these spines are designed not to break off of the cactus even if you run into them. Others – and these are the dangerous ones – are as thin as hair and are designed to break off into your skin at the slightest touch and be almost impossible to cleanly remove.
The poke factor of these spines are all that’s keeping the cactus from being eaten by hungry animals (aside from some cacti which have poisonous meat – but still no poisonous spines).

Getting pricked by a cactus can lead to infection or an allergic reaction.
Getting pricked by a cactus can lead to an allergic reaction. This is an extremely rare thing, so chances are overwhelmingly likely that you’ll never experience an allergic reaction from a cactus spine, but it could still happen.
If you have any of the following symptoms, seek medical attention immediately:
- swelling of your tongue, mouth or throat
- trouble breathing
- rashes/hives/itching
- dizziness/weakness
If there is a spine left behind in your skin that you don’t remove, it can cause an infection. Spines of cacti often have bacteria on them and are designed to break off inside of your skin when you try to pull them out.
This means that pieces of them can get lodged into your body and take weeks or months to completely work themselves out. Once, for example, I was stuck by a thorn that took almost a year to fully stop hurting – I suspect because part of it broke off inside of my skin.
Because of this, you’ll want to pull it out gently with clean tweezers. Wash the area with soap and water, then apply a topical antibiotic or antibacterial ointment.
You may also wish to cover the wound with a bandage and continue to use antibacterial ointment with pain reliever if it is still sensitive to being touched or rubbed up against.
Cacti are not for everyone.
Now that you’ve read all about cactus spines, remember:
If you have any kind of allergies, opt for friendlier succulents without hair or spines. Some people can handle the prickles with no issues while others can get a rash from merely brushing up against one.
As for children and pets, it’s best to keep them away from your cacti for obvious reasons. If you have either, it may be best to avoid getting cacti.
Even then, be careful when handling them as some humans are allergic to the sap – especially those with latex allergies – and others may be allergic to the hairs of these plants. It’s sometimes recommended that individuals who are particularly sensitive refrain from handling their own cacti because they can develop an allergy over time!
It’s best just not to handle a prickly pear if you’re not comfortable with it—or even better yet, don’t try to keep a cactus at all! Cacti are not for everyone.

Takeaway: Cactus spines may be irritating, but they’re generally not dangerous.
So, is it true that cactus spines are poisonous?
Not really. Cacti in the wild produce a number of toxins that help them survive in harsh environments, but none of them are present in their spines.
While you’re unlikely to suffer long-term complications from a prick, they can cause mild irritation and redness. For most people, this will go away on its own after an hour or two, though those with sensitive skin may want to consider applying some antihistamine cream or ointment to speed the process.
However, if your symptoms persist longer than a week or become more severe, be sure to see a doctor right away.