Aspirin and paracetamol: which to choose?

The safest choice isn't necessarily the strongest painkiller – it's the one that's appropriate for your symptoms and overall health.

How aspirin and paracetamol work

When a headache strikes, your back starts aching or a fever leaves you feeling miserable, reaching for a painkiller can seem like the obvious answer. But not all painkillers work in the same way. Two of the most familiar options are aspirin and paracetamol. So, how do you know which one to choose?

Aspirin belongs to a group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs). It helps relieve pain and reduce fever, but it also reduces inflammation. “Aspirin works by blocking substances in the body called prostaglandins, which contribute to pain, inflammation and fever,” says Cara de Lange, acting pharmacy manager at Mediclinic Stellenbosch and Mediclinic Winelands Orthopaedic Hospital. “It also makes platelets in the blood less sticky, which is why low-dose aspirin is sometimes prescribed to help prevent blood clots.”

Paracetamol also reduces pain and fever, but it has little anti-inflammatory action compared with aspirin. That’s why it’s often used for headaches, toothache, muscle aches, period pain, colds and flu, and fever.

When might aspirin be useful?

Because aspirin has anti-inflammatory properties, it may be helpful for some types of pain where inflammation is involved. It can also be used for conditions such as arthritis, although other medicines may be preferred depending on the person and their medical history.

However, aspirin isn’t suitable for everyone. “One of its main drawbacks is that it can irritate the stomach and increase the risk of stomach ulcers and bleeding,” says De Lange. “Because it affects blood clotting, the risk of bleeding can be particularly important for people taking blood-thinning medication or those with some bleeding disorders.”

Aspirin should also not generally be given to children or teenagers with viral infections because of the risk of a rare but serious condition called Reye's syndrome.

When is paracetamol the best choice?

Paracetamol is often considered a first-choice option for mild to moderate pain and fever. It tends to be gentler on the stomach than aspirin and does not have the same effect on blood clotting.

This can make it a more appropriate option for some people who cannot take NSAIDs. “However, ‘gentler’ does not mean risk-free,” De Lange cautions. “Taking too much paracetamol can cause serious liver damage, and an overdose can be life-threatening.”

One of the biggest risks is accidentally taking paracetamol from more than one source. “Many cold and flu remedies contain paracetamol, so always check the active ingredients before combining medicines.”

Aspirin or paracetamol for a headache?

For an ordinary headache, either may provide relief for many adults, depending on individual circumstances. “Paracetamol may be preferred if you have a sensitive stomach or cannot take NSAIDs, while aspirin may be useful when inflammation is contributing to the pain,” De Lange says.

However, frequent headaches should not simply be treated repeatedly with painkillers. Regular overuse of headache medication can itself contribute to headaches. If headaches are persistent, severe, or change in pattern, speak to a healthcare professional.

What about a fever?

Both aspirin and paracetamol can reduce fever. “Paracetamol is commonly used for this purpose because it reduces temperature without stomach irritation and blood-thinning effects associated with aspirin,” says De Lange.

It bears repeating that aspirin should not be given to children because of the risk of serious adverse effects. An age-appropriate paracetamol product and dose should be used instead.

If paracetamol doesn’t provide adequate relief, consult a healthcare professional to investigate the cause and consider alternative treatment options.

Can you take aspirin and paracetamol together?

Sometimes adults may be advised to use both medicines, but this isn’t something you should routinely do without checking whether it’s appropriate for you. Taking multiple medicines increases the possibility of side effects, interactions, or accidentally exceeding recommended doses.

“It’s particularly important to speak to a doctor or pharmacist if you take regular medication, are pregnant, have kidney or liver problems, have a history of stomach ulcers or bleeding, or have another chronic health condition.”

The bottom line

Aspirin and paracetamol can both be effective painkillers, but they have important differences.

Aspirin can reduce pain, fever, and inflammation but may irritate the stomach and increase bleeding risk.

Paracetamol is effective for pain and fever and is generally easier on the stomach, but it’s not an anti-inflammatory. Taking too much can also seriously damage your liver.

Always follow the dosage instructions on the package or those provided by your healthcare professional and ask a pharmacist or doctor if you’re unsure which option is right for you.