Antibiotics and painkillersSpec 4.3.1.8
In short
Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body. Specific bacteria should be treated with specific antibiotics. Antibiotics cannot kill viruses, and the emergence of strains resistant to antibiotics is of great concern. Painkillers and other medicines treat the symptoms of disease but do not kill pathogens.
Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body.
It is important that specific bacteria are treated by specific antibiotics.
The use of antibiotics has greatly reduced deaths from infectious bacterial diseases. However, the emergence of strains resistant to antibiotics is of great concern.
What antibiotics cannot do
- Antibiotics cannot kill viral pathogens.
- It is difficult to develop drugs that kill viruses without also damaging the body's tissues, because viruses live and reproduce inside cells.
Painkillers
Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens.
| Antibiotics | Painkillers | |
|---|---|---|
| What they do | Kill bacteria inside the body | Treat symptoms such as pain |
| Do they kill pathogens? | Yes, bacteria only | No |
| Work on viruses? | No | They do not kill them, but can ease symptoms |
If asked why an antibiotic is not given for a viral illness, say that antibiotics cannot kill viruses. Do not say that viruses are 'too small'.
Written and checked against the AQA GCSE Combined Science (8464) specification · Updated October 2026