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Unusual appearances of breastmilk

What colour is breastmilk?

The colour of breastmilk varies. Colostrum is typically yellowish and mature breastmilk is typically bluish-white. However, there is a wide range of normal when it comes to the colour of breastmilk. Most mothers are unaware of the colour of their breastmilk, unless they express.

In most cases, the colour of a mother’s breastmilk is nothing to be worried about. However, it is always a good idea to seek medical advice if you are concerned.

An unusual colour of a mother’s breastmilk could be due to her diet. For example, food dyes in foods or drinks can alter the colour of breastmilk.

            Pink breastmilk

This can be caused by eating a large amount of strongly-coloured foods such as beetroot. It can also sometimes indicate blood staining. See below under ‘Blood in breastmilk’.

            Yellow/orange breastmilk

This can be caused by eating a large amount of orange-coloured foods such as carrots, squash or pumpkin.

            Green breastmilk

This can be caused by eating large amounts of green (or even blue)-coloured foods such as green vegetables, kelp and other types of seaweed in tablet form or concentrates of natural vitamins. Blue dyes in foodstuffs sometimes cause breastmilk to be green-tinged.

            Black breastmilk

This can be caused by some medications (eg oral Minocycline therapy for acne). Black breastmilk can also indicate blood staining. See below under ‘Blood in breastmilk’.

            Red/brown breastmilk

This usually indicates blood or broken down blood products. See below under ‘Blood in breastmilk’.

            Bright white lumps

Often this is just the cream that naturally rises to the top of the milk once it sits in a container for any length of time. 

Blood in breastmilk

In most cases, blood staining in breastmilk does not indicate a serious medical condition (eg breast cancer), but a mother should see a doctor to have this ruled out. It is common to have blood-stained colostrum or milk in the first days after giving birth. This is referred to as 'rusty pipe syndrome' and is thought to be as a result of the growth of the ducts and milk-making cells in the breast and does not persist beyond about 7 days. Bright red, pink, coffee/chocolate brown, black or olive green coloured breastmilk may suggest the presence of blood. The most common cause of blood in breastmilk is a cracked nipple. A less common condition that may cause blood in breastmilk is an intraductal papilloma — a small benign wart-like growth on the lining of a milk duct, which bleeds. This not breast cancer and usually resolves in a few days. It is still a good idea to see a medical adviser.

Occasionally a baby may pass dark bowel motions or may spit up blood-stained milk. This is usually a result of the baby drinking blood-stained breastmilk rather than the blood coming from the baby. It often looks like a lot of blood because the blood can form one large lump in the stomach, which the baby spits up. Swallowed blood will not harm the baby, but tends to irritate the stomach and makes vomiting more likely. However, it is always worthwhile seeking immediate medical advice in these situations.

Unusual taste/odour of breastmilk

A change in the taste and smell of stored breastmilk can occur due to an enzyme called lipase (which naturally occurs in breastmilk) breaking down fat into fatty acids. It is not harmful but some babies may dislike the taste. This doesn’t happen to many mothers, but tends to persist in an individual mother’s breastmilk. To avoid this, mothers who find this happens can scald their milk soon after expressing and before storage to decrease lipase activity.

Some mothers have found that their breastmilk can smell like the food they’ve eaten (eg garlic). This is one of the good things about breastfeeding, as your baby learns about the flavours in your family diet even before starting solids. Other possible causes include food odours being absorbed into stored breastmilk from the fridge/freezer or storage containers being used. As long as the breastmilk has been stored correctly, the breastmilk is quite safe to use. 


Baird K (1998), Unusual Appearances of Breastmilk. Regional File B5 Nursing Mother’s Association of Australia

Lawrence R, Lawrence R 2010, Breastfeeding A Guide for the Medical Profession (7th ed). Saunders publishing Philadelphia

Spitzer J, Doucet S, Buettner A 2010, The influence of storage conditions on flavour changes in human milk. Food Quality and Preference 21(8):998-1007

© Australian Breastfeeding Association August 2017

 The information on this website does not replace advice from your health care providers.

Last reviewed: 
Aug 2017