Mastitis is a condition that causes the breast tissue to become inflamed. It usually occurs in women who are breastfeeding, so it is often referred to as lactation mastitis.

Mastitis usually affects only one breast, causing it to become painful, red and swollen. Some women may also experience flu-like symptoms, which can include fever, chills or aches.

Types of mastitis

There are two main types of mastitis:

  • non-infectious mastitis, which is typically caused by breast milk remaining within the breast tissue (milk stasis), and is due to a blocked milk duct or problems with breastfeeding, and
  • infectious mastitis, which is caused by bacteria.

Left untreated, non-infectious mastitis can progress to infectious mastitis. This may be due to bacteria infecting the milk that remains in the breast tissue.

Infectious mastitis requires prompt treatment in order to prevent more serious complications such as an abscess in the breast.

How common is mastitis?

There have been a number of studies that have tried to estimate how many women are affected by mastitis. Results have varied and estimates have ranged from 3% to 33%, but most studies agree that around 10% of all breastfeeding mothers are affected by mastitis.

Most women will develop mastitis during the first three months after giving birth, but it can occur up to two years after giving birth.

The importance of continuing to breastfeed

Though the symptoms of mastitis may discourage you from continuing to breastfeed it is important to continue. Regular breastfeeding will help remove any "blocked" breast milk from your breast, should help resolve the symptoms faster and help prevent mastitis from becoming more serious.

Though the milk from the affected breast can be a little saltier than normal, it is perfectly safe for your baby to drink. Any bacteria that may be present in the milk will be harmlessly absorbed by your baby's digestive system and cause no problems.

Self-help techniques

Most cases of mastitis can be successfully treated by using a number of self-help techniques, such as feeding your baby more frequently, or expressing any excess milk after a feed.

More serious cases of infectious mastitis will require antibiotics to bring the infection under control.


Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.


A fever is when you have a high body temperature (over 38C or 100.4F).


An ache is a constant dull pain in a part of the body.


Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.


An abscess is a lump containing pus. Pus is made by the body during infection.


Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. Examples of antibiotics are amoxicillin, streptomycin and erythromycin.
Last updated: 04 October 2011

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