When is dark menstrual blood a cause for concern?

Doctor's Answers (3)

Dr Paul Ang

"Family Physician with special interest in Mental Health"

Thank you for asking this interesting question Hazel, I am sure many patients are keen to know as well.

If you remembered some chemistry from your school days, iron oxidises, or rusts. So the longer the iron or the lining has been in your body, the more likely it will "rust" inside.

It is absolutely normal to have brownish or even black colour menses on the first few days. But of course if you are worried, you can see a GP or Gynae to have it checked.

Take care!


The colour of your period blood can vary from cycle to cycle. As a rule of thumb, the color of menstrual blood is a shade or two darker than "normal" bleeding, like say, if you were to cut yourself. 

As Dr Paul has mentioned, the color of your menstrual blood is essentially a sign of how quickly the blood is passing through.

The brighter red it is, the more recent the bleeding and the quicker the blood is passing through your cervix and into the vagina.

The darker the flow (which can range from dark red to brown) the more likely it is to be older blood, or experiencing slower flow.  

This is because when blood takes extra time to exit the uterus, the iron inside blood oxidizes, which causes it to appear dark brown or black in color. It may even resemble coffee grounds.

Very occasionally, dark coloured period blood could be a sign of other things, such as an infection. This is usually accompanied by foul-smelling discharge. Thus, if you are concerned, you should probably see a GP and explain your symptoms, as well as your history.


Just like what Dr Ang has mentioned, dark-colored menstrual blood can be considered normal, and you do not have to worry if you do not experience other accompanying symptoms. 

However, from a holistic approach, a TCM practitioner would inquire further to find out if you suffer from menstrual pain and if you do, does it happen before, during or after the period; is your menstrual cycle regular; any fertility issues etc. 

According to TCM, dark menstrual blood is seen as stagnated blood (血瘀). It may be due to poor circulation (coldness) in the womb where one may be born with a 'cold' body type, or tends to binge on chilled/raw food and drinks. 

Typically, a physical consultation is necessary to determine which type you belong to, before a treatment plan can be formulated specially for you. 

Do speak to your healthcare provider about your concerns so that it may be addressed effectively. 

I hope it helps!

Best wishes, 
Physician Lee

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