Abnormal colours of milk

Why has my milk changed colours?

There are several reasons why breast milk changes colours. These include the normal change in breast milk colour from creamy yellow to a pale blue during the months after birth; mammary duct ectasia, which may turn the milk green; and a bacterium (Serratia marcescens) that turns it pink. Medication, vitamin preparations, sports drinks, gelatin, and other foods and drinks that contain a lot of dye may change the colour of milk to one of several possible colours. Managing the colour change depends on its cause.

A) Reasons for colour change of breast milk

Milk can change colour. The colour is determined by the cause of the colour change and may be normal, related to food or medication the mother has taken in, or due to infection or breast disease. Similarly, managing the colour change depends on its cause and may include changes in diet or medication or treating infection or breast disease. 

B) Pale blue milk

1) Normal changes in colour with age

Breast milk changes colour as the baby grows, from creamy yellow to pale blue, much like the colour of skim-milk.

2) Normal changes in colour with the amount of fat

The fat content of breast milk increases as the baby feeds or the mother expresses. The lower-fat milk that a baby gets early in the feed is called foremilk and the richer milk from later in the feed is called hindmilk. Foremilk is more likely to be pale blue and hindmilk more creamy yellow. Some mothers unnecessarily worry about fore- and hindmilk.

C) Green milk

Green colostrum.

1) Green colostrum

While usually straw-coloured, colostrum can also be green.

2) Mammary duct ectasia

Mammary duct ectasia happens when a milk duct under the nipple becomes wider and fills with fluid. It can result in green or even black secretion from the nipple. The area is also more prone to becoming infected.

3) Pill use

Breast milk may be green if mothers take in:

  • Iron (Rainone 2018).
  • Blue-green algae pills (Naor 2019).
  • The sedative propofol (Rainone 2018).

D) Pink milk

1) Contamination with the bacterium Serratia marcescens

Contamination of breast milk by the bacterium Serratia marcescens can turn breast milk pink (Quinn 2018). Babies who drink this milk may develop pink diapers and should be examined for other signs of infection. The bacteria may be introduced by techniques used to express and store breast milk. These techniques should be reviewed. Mothers should see their health-care providers to discuss possible treatment for themselves and their babies (Quinn 2018). 

2) Antibiotic use

Mothers using the antibiotic clofazimine may have pink milk (Anderson 2018).

F) Black milk

Mother’s milk may turn black if they are using the sedative propofol or the antibiotic minocycline (Eisen 1998).

G) Various colours

Certain vitamin preparations, sports drinks, gelatin, and other foods and drinks that contain a lot of dye may change the colour of milk (Thompson 1943; Yazgan 2012). In this situation, it is not necessary to stop breastfeeding but mothers may want to review their diet.


Anderson PO. Unusual Milk Colors. Breastfeed Med. 2018 Apr;13(3):172-173

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Naor N, Fridman E, Kouadio F, et al. Green Breast Milk Following Ingestion of Blue-Green Algae: A Case Report. Breastfeed Med. 2019 Apr;14(3):203-204
Quinn L, Ailsworth M, Matthews E, et al. Serratia marcescens Colonization Causing Pink Breast Milk and Pink Diapers: A Case Report and Literature Review. Breastfeed Med. 2018 Apr 30
Rainone A, Delucilla L, Elofer S, et al. Propofol-Induced Green Breast Milk: A Case Report. Can J Hosp Pharm. 2018 Nov-Dec;71(6):389-391
Thomson ML. Carotinaemia in a suckling. Arch Dis Child 1943;18:112
Yazgan H, Demirdoven M, Yazgan Z, et al. A mother with green breastmilk due to multivitamin and mineral intake: a case report. Breastfeed Med 2012;7:310–312