The Center for Podiatric Care and Sports Medicine

Why Is My Toenail Black?!

Posted by on Thursday, March 1st, 2012


It is a disconcerting sight, if you look down and see that one of your toenails is black. It is especially alarming if you are quite sure that you are not wearing black nail polish.

So why on earth would your toenail turn black? Is it in a bad mood? Is it trying to make a fashion statement? Has it just been overtaken by an angry gremlin who wants to scare you?

In most cases, the answer is quite simple and nothing to be alarmed about; it’s not like you’ve just contracted C. difficile or something truly ugly like that. Generally, a blackened toenail is a sign that your poor little big toe has undergone some kind of trauma and a bruise or blood blister forms under your toenail. The black color comes from blood that has pooled under your nail.

Causes If you’ve had something happen to your toe, perhaps if you’ve dropped a table on it (yes, I did that once at a catering job), then you can expect to see a black toenail in a day or two. However, black toenails are most common in runners and serious walkers who are repeatedly striking the ground hard with their toes. For some people, a black toenail is a sign that their running shoes or socks are too tight. Remember, you really should make sure there’s about a half inch of space between the top of your toes and the front end of the shoe.

Many hardcore runners will find themselves with a black toenail just from hard training, though, even if their shoes fit perfectly. Repeated stress on your toe as you land on it over and over will catch up with you after a while. If you’re training for a marathon, don’t be surprised if you’re greeted one day by a black toenail on your foot. It’s just part of the deal. This is especially likely if you run downhill often, where your toe is absorbing a lot of force, or if your running in hot weather when your feet will swell.

What if you don’t have any of these things going on in your life, though? No tables dropped on your toe, you’re more likely to be caught relaxing on a beach than running on pavement, and your shoes fit perfectly. If that’s the case, then you should see a doctor–it’s possible you might have a melanoma forming.

The Treatment For garden variety black toenails caused by trauma, bad-fitting shoes or running, the best thing to do is just leave it alone. It may hurt for a day or so, like an ordinary bruise. If it’s distractingly painful, you can take some ibuprofen or acetaminophen, but you don’t want to down that stuff like candy at every little twinge. After a while, a new toenail will begin to grow under the old nail. The blackened one will begin to loosen and eventually fall off. Don’t try to hurry it along–first, the old toenail is acting as a protective shield for your tender nailbed until the new one is long enough to cover a good deal of it. Second, that old nail is still attached to some skin, so the only way to get it off is to really rip it. This hurts a LOT and bleeds, too. I can guarantee this because, well, I’ve done it.


If you’re really brave, and really annoyed by this blood under your toenail, you can take sterilize a needle or paper clip in a flame, pierce the skin, and drain out the blood yourself. Jeff Galloway has precise instructions for doing this. If you’re really brave. Like Jeff Galloway. If you’re me,  you just sit back and enjoy the process of watching your toenail slowly loosen and fall off.

Avoiding It As we said above, you can avoid blackened toenails by making sure your shoes fit properly, but if you’re a serious runner, you probably can’t avoid it. In that case, don’t worry about it and be prepared for people to scream if you’re wearing open toed shoes and they happen to notice your threatening, dangerous black toenail. Or you can paint all your other toenails black and make it all look like a plan.

If you keep suffering from black toenails, or don’t feel your black toenail is the result of the common causes, don’t hesitate to contact us at The Center for Podiatric Care and Sports Medicine. Dr. Josef J. GeldwertDr. Katherine Lai, and Dr. Ryan Minara have helped thousands of people get back on their feet.



If you have any foot problems or pain, contact The Center for Podiatric Care and Sports MedicineDr. Josef J. GeldwertDr. Katherine Lai, Dr. Ryan Minara and Dr. Mariola Rivera have helped thousands of people get back on their feet. Unfortunately, we cannot give diagnoses or treatment advice online. Please make an appointment to see us if you live in the NY metropolitan area or seek out a podiatrist in your area.