The colour and consistency of blister fluid can range from thin and colourless, to a thick stringy yellow, to all shades of pink, red, dark purple and also black. Each colour tells you something specific about your blister. So, in this article, you’ll discover what’s inside your blister to make it looks the way it looks. And what it all means.


Normal “healthy” blisters have a thin colourless liquid in them. This normal blister fluid is similar to plasma but has a lower protein level. Plasma is basically blood without the red blood cells. In fact, it’s mostly water, which is why blisters normally have no colour.


Pus is yellow (or sometimes green) and thicker than the normal fluid found in blisters. It can even be a bit stringy in its consistency. It consists of dead white blood cells and bacteria with tissue debris and serum. The presence of pus means your blister is infected.

Normal blister fluid is thin and colourless. The blister fluid in an infected blister is thicker and yellow (pus).

Normal blister fluid is thin and colourless, whereas the liquid contents of an infected blister is thicker and yellow (pus).

Learn more about the other signs of infected blisters here

3) PINK / RED / PURPLE – Blood

When there’s a bit more pin-point pressure involved in the blister injury, blood vessels slightly deeper to the normal blister can be damaged. As a result, blood enter the blister and mixes with the normal fluid. The more blood that enters, the more red it will be. After that, as the days go by and the blood dries, the colour gets darker and turns to a dark purple or even black colour.

There are three blisters here. One is a typical blister (top right). The other two are blood blisters with varying amounts of blood in them, which effects the colour. here's also a callous involved with one of these blisters that might throw you off, so just thought I'd point that out.

There are three blisters here. One is a typical blister (top right). The other two are blood blisters with varying amounts of blood in them, which effects the colour. There’s also a callous involved with one of these blisters that might throw you off, so just thought I’d point that out.



Wrapping up the colours of blisters

  • Yellow or green infected blisters are the worst blisters to have. That’s because infections can be dangerous if left enchecked.
  • Pink, red or purple blisters are usually the most painful. By the time they become black they’re usually not so painful.
  • Other than that, colourless blisters are the best blisters to have – if there is a good blister to have?


You’ll find the tools and instructions you need to do this safely, and painlessly, in our Blister Lance Pack. Click the “view product” button below to learn more about what’s in this blister kit and how to use it.

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Rebecca Rushton BSc(Pod)

About The Author

Rebecca Rushton BSc(Pod)

Podiatrist, blister prone ex-hockey player, foot blister thought-leader, author and educator. Can’t cook. Loves test cricket.

USD $11.99BlisterPod Sterile Blister Lance Pack

Blister Lance Pack

Got a blister that needs popping? Don't use scissors or a sewing needle & get infected. Do it safely with our Sterile Blister Lance Pack.



  1. Julie Ann Quintana 28 February 2022 at 1:08 am - Reply

    Hello. I have a blister on top of my toe. It’s been there for almost a year. Every time I pop it, it is filled with a clear, viscous, sticky, gel-like substance. And no matter what I do, it keeps coming back. I clean it with alcohol, soap & water, and nothing at all. I’ve pierced it with a needle to drain it, pulled the top completely off, and left it open to the air and/or covered with a bandaid (with Neosporin and without). I’ve left it to scab up and heal COMPLETELY only to have another appear in the exact same spot by the time it’s healed. If I pick the scab off or pop it again . . . Again, goo ! I’m about to take my son’s advice. “Kill it, mom ! Kill it with fire !” He thinks it’s from space. LOL Any recommendations?

    • Rebecca Rushton BSc(Pod) 3 March 2022 at 5:47 pm - Reply

      It’s not a blister Julie Ann. Please see your doctor.

    • Luis 28 March 2023 at 8:53 am - Reply

      I have the same ? What ended up happening

  2. Alex omar 12 July 2022 at 1:39 am - Reply

    I have a blister and it’s filled with”milk” and there’s no sign of infection even my doctor confirmed it!what’s wrong ?

    • Rebecca Rushton BSc(Pod) 12 July 2022 at 8:21 am - Reply

      It sounds atypical. Exactly the type of thing you need to actually see someone about rather than have someone guess blind. Go back to the doctor and get more guidance than simply “it’s not infected”. For example, is it a friction blister, allergy blister or something else. The cause will obviously guide treatment. Sorry I can’t help more from here.

  3. Jon 4 August 2022 at 3:22 am - Reply

    Why do poison Ivy blisters have a yellow-orangish, gooey serum?

  4. Gabriella Powell 22 October 2022 at 8:51 pm - Reply

    I got a blister from a hot glue gun burn and now it’s a light orange/brown color…
    What should I do?

    • Rebecca Rushton BSc(Pod) 22 October 2022 at 8:53 pm - Reply

      See a doctor, Gabriella. I only advise of friction blisters of the feet, being a podiatrist.

    • Tracy 7 May 2023 at 11:46 pm - Reply

      I have a blister on the back of my tendon it’s a large blister draining a clear watery yellow tint fluid I had it for a week it doesn’t hurt only itch went I clean it.

  5. Janet 29 October 2022 at 1:37 pm - Reply

    I have undergone bilateral hip replacement and developed a friction blister on left heel, slightly under. It was not seen because of compression and I was in a unit which offers hydro pool and physio twice daily. The blister was intact and was left by physios and I thought a Compeed hydrocolloid dressing would work. I, the patient cannot reach or see it – hip precautions. It’s stayed on 5 days and was working, 2nd plaster went on but was removed by nurse following day and I was discharged. I was pretty unhappy. I’m now home and trying to persevere with Compeed but it is difficult to achieve a seal. I think Mepilex may be better but I am now self caring on my own and the Compeed comes off in bed. Also it’s difficult to keep backs of heels off the sheets. I am in the UK but would be grateful for advice for what I can buy here that can be applied by a non professional

    • Rebecca Rushton BSc(Pod) 29 October 2022 at 5:15 pm - Reply

      This sounds more like a “pressure sore”, Janet. I can’t get an accurate picture from your description to be able to advise you on this. Please present to your doctor, wound care nurse or podiatrist for the best advice.

  6. Jane 6 November 2022 at 3:13 am - Reply

    I have a blister that has a yellow liquid inside it from an insect bite, I thought it was just a normal gnat bite but has since turned into a blister on back of ankle and is very hard and yellow in colour

    • Jane 6 November 2022 at 3:14 am - Reply

      Just to add I haven’t been to see doctors yet I’m just wondering if this sounds infected and what should I do to help it go quicker

  7. Alliena Westleigh 25 December 2022 at 5:11 am - Reply

    My mother fell and sprained her ankle (doctor X-ray said it not broken)
    Now her foot is blistering really bad. Is that normal? Some are orange, some are black and purple.

    • Rebecca Rushton BSc(Pod) 29 December 2022 at 9:17 am - Reply

      No it’s not normal, Alliena. You’ll need to seek medical advice with this. I only advise on friction blisters of the feet.

  8. Tiffany 4 April 2023 at 1:38 am - Reply

    I have a blister that developed after allergic reaction. It popped. The liquid that came out was a brownish color. Do I need to see a doctor for that

    • Rebecca Rushton BSc(Pod) 8 April 2023 at 6:01 pm - Reply

      Consult with your doctor, Tiffany.

  9. Diane 8 May 2023 at 3:46 pm - Reply

    Any idea on how to treat skin discoloration. The darkness scar left over from where there was a blister? Doc says its superficial and should eventually go away but I’d rather not sit back for a year and allow it to not become lighter. I’m using bio oil now with no differences shown yet. I do have silicone scar tape i could use.

    • Rebecca Rushton BSc(Pod) 8 May 2023 at 3:48 pm - Reply

      I’m not aware of anything you can do that will make any difference.

  10. Geoff 10 May 2023 at 1:39 pm - Reply

    Hi Rebecca,

    I’m a server / bartender at a busy restaurant, and it seems whenever I take time off and go back to work I almost have to wear my feet in again. I’ve got matching purple / black blisters in two days on my feet in almost the exact same place. Ideas?

    • Rebecca Rushton BSc(Pod) 10 May 2023 at 1:54 pm - Reply

      Yes, your skin deconditions if you don’t apply the shear loads to it for a while. And as you gradually expose it to those loads, the skin changes in structure to become more resistant to the mechanical fatigue of blisters. Only to lose it again when you’r eon holiday.

      As for blisters in the same place – yes, sounds pretty run of the mill. You’ll have a structural or functional predisposition to blisters at that anatomical site. If you want to know more about what causes those blisters and how to prevent them, search for the anatomical location eg: back of heel.

  11. Ashley 22 May 2023 at 5:21 am - Reply

    Why would friction blisters appear to have small white lumps in the fluid?

  12. sabina 26 May 2023 at 3:12 am - Reply

    i have a blister ( 2″ diameter) from an insect bite that first drained a clear yellow fluid but has filled up again, this time red and bluish in color and it is not draining … this is day 5, there’s no pain, just very itchy … do i need to see a doctor??

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