Antibiotics and painkillers: Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens.

The idea

Painkillers such as paracetamol relieve symptoms like headache, fever or pain, but they do not destroy the pathogen causing the infection. They act on the body's pain and temperature pathways rather than on bacteria or viruses, so the immune system must still clear the pathogen. Other medicines may also treat symptoms without killing pathogens; for example, oral rehydration solutions replace water and ions lost through diarrhoea, and antihistamines reduce allergic symptoms. This contrasts with antibiotics, which kill bacteria or stop their growth. A patient with a bacterial throat infection may take a painkiller to reduce soreness while an antibiotic kills the bacteria. Understanding this distinction prevents the misconception that any medicine that makes you feel better is fighting the infection itself.

What earns the marks

• Painkillers relieve symptoms such as pain, fever or inflammation but do not kill pathogens.
• Painkillers act on the body's symptoms rather than on the pathogen itself.
• Other medicines, such as oral rehydration solutions, treat symptoms or replace lost substances without killing pathogens.
• Antibiotics are different because they kill bacteria or inhibit bacterial growth.
• The immune system still has to destroy the pathogen when only symptom-relieving medicines are used.
• A named example, such as paracetamol for a headache, can illustrate symptom relief without pathogen destruction.

Common mistakes and how to put them right

• Thinking that painkillers kill the pathogen because the patient feels better.

  Put it right: Painkillers only relieve symptoms, and the immune system or another medicine must remove the pathogen.

• Confusing painkillers with antibiotics.

  Put it right: Antibiotics target bacteria, whereas painkillers do not kill bacteria or viruses.

• Assuming all medicines are antibiotics.

  Put it right: Medicines include symptom relievers such as painkillers and rehydration solutions as well as antibiotics.

Exam tips

• State clearly that painkillers treat symptoms and do not kill pathogens, using the word 'symptom' explicitly.
• Contrast painkillers with antibiotics in one sentence to show the difference in action.
• Use a named example such as paracetamol or ibuprofen to support the explanation.