Blood poisoning


Sepsis is a life-threatening illness caused by the body overreacting to an infection.

The body’s immune system goes into overdrive, setting off a series of reactions that can lead to widespread inflammation (swelling) and blood clotting.

Symptoms usually develop quickly and include:

  • a fever or high temperature over 38C (100.4F)
  • chills
  • a fast heartbeat
  • fast breathing

In severe cases you may notice:

  • you feel dizzy when you stand up
  • confusion or disorientation
  • nausea and vomiting

Read more about the symptoms of sepsis.

Although anybody can develop sepsis from a minor infection, some people are more vulnerable, such as those:

  • with a medical condition or receiving medical treatment that weakens their immune system
  • who are already in hospital with a serious illness
  • who are very young or very old
  • who have just had surgery or who have wounds or injuries as a result of an accident

Read more information about the causes of sepsis.

Stages of sepsis

Sepsis develops in three stages, described below.

  • Uncomplicated sepsis is caused by infections, such as flu or dental abscesses. It is very common and does not usually require hospital treatment.
  • Severe sepsis occurs when the body’s response to infection has started to interfere with the function of vital organs, such as the heart, kidneys, lungs or liver.
  • Septic shock occurs in severe cases of sepsis, when your blood pressure drops to a dangerously low level, preventing your vital organs from receiving enough oxygenated blood.

If it is not treated, sepsis can progress from uncomplicated sepsis to septic shock and can eventually lead to multiple organ failure and death.

If you think you have sepsis, it is important to get it diagnosed and treated as quickly as possible.

If you think that you or someone in your care has severe sepsis or septic shock, phone 999 and ask for an ambulance.

Read more information about how sepsis is diagnosed.

Treating sepsis

If sepsis is detected early and has not yet affected vital organs, it may be possible to treat the infection at home with antibiotics. Most people with uncomplicated sepsis make a full recovery.

Severe sepsis and septic shock are considered medical emergencies and normally require admission to an intensive care unit, where the body’s organs can be supported while the infection is treated.

Because of problems with vital organs, people with severe sepsis are likely to be very ill, and approximately 30-50% will die as a result of the condition.

Read more information about how sepsis is treated.

How common is it?

It is estimated that there are over 30,000 cases of severe sepsis in the UK every year, and the number seems to be rising.

Last updated: 26 March 2014

Continue to next section: Symptoms of sepsis