There are few things more irritating than lying in bed exhausted, ready to settle in for a good night’s sleep, only to be kept awake by a cough that won’t quit.

So, if you’re desperate to make it stop, what actually works?

Most coughs don’t needed to be treated, and though annoying, will go away by themselves.

So if you’re tempted by the many lozenges, syrups or medicated hot drinks that promise to ease that dry, itchy feeling in your throat, here’s what to keep in mind.

First, what’s causing the cough?

A cough is a symptom and protective reflex to clear your airways, rather than an illness itself.

Many coughs are caused by short-lived viral infections and can be safely managed at home, but others are caused by conditions that need medical assessment or specific treatment.

A cough that brings up mucus from the lungs is often described as chesty or productive.

A dry cough produces no mucus, or a small amount that comes from the nasal passages. Dry coughs are commonly caused by viral infections but can also signal other conditions.

Any cough that lasts longer than four weeks should be assessed by your GP, while any severe or worrying symptoms, such as difficulty breathing or swallowing, blood or chest pain, should prompt you to seek urgent care.

What is in cough medicines?

There are three main kinds of cough medicine ingredient.

Antitussive agents such as dextromethorphan, also known as cough suppressants, reduce the cough reflex.

Other ingredients make the mucus easier to cough up, either by breaking it up (mucolytics such as bromhexine) or by thinning and loosening it (expectorants, including guaifenesin).

These ingredients may be found in some cold and flu tablets, as well as in cough syrups, lozenges and medicated hot drinks.

So which, if any, work?

Cough syrups

Cough syrups are typically marketed based on the type of cough.

Syrups for dry cough are supposed to help you stop coughing using a cough suppressant, while chesty cough syrups use a mucolytic or expectorant to make the mucus easier to cough up.

Products that claim to help with both … well, they just don’t make sense.

There isn’t much good evidence to show cough syrups work, as they haven’t been tested well enough. This is partly because they were added to the market decades ago, when clinical trials didn’t have the same standards as today.

When it comes to cough suppressants, there is good evidence detromexthorphan is effective. But you should be aware of potential side effects, including nausea and drowsiness, and always follow the label.

There is little evidence another common cough suppressant, dihydrocodeine, works. As an opioid, it can also be misused, which is why it’s kept behind the counter, sold only with a pharmacist’s supervision.

Pholcodine, another cough suppressant, was removed from Australian pharmacy shelves in 2023 due to safety concerns. It can cause the immune system to overreact to muscle relaxants used during general anaesthesia – even if you’ve taken it years before an operation – and be life-threatening.

The evidence is similarly limited for medicines used to break up and thin mucus in a chesty cough, such as bromhexine and guaifenesin, although these don’t have the same safety concerns as pholcodine.

So overall, there is limited good-quality evidence that cough mixtures help improve a cough, except for the cough suppressant dextromethorphan.

And there is no evidence that cough medicines work in children, and they’re not recommended.

Much of the perceived benefit of cough mixtures may actually come from the soothing effect of a thick, sweet liquid, together with the fact most viral coughs improve naturally over time.

The case for the efficacy of cough medicines is weak. Photo: Unsplash

Cough lozenges

Lozenges may temporarily soothe your throat, but there’s little evidence they reduce cough duration.

Some lozenges contain herbal ingredients that aren’t always safe in people with allergies. For example, andrographis has been linked to rare but serious allergic reactions including anaphylaxis.

Medicated hot drinks

Medicated hot drinks are typically a powder that you add to hot (not boiling) water.

They tend to contain paracetamol, vitamin C and phenylephrine, which has been shown to have little to no effect as a decongestant when taken orally.

If you have fever or body aches, the paracetamol may help relieve these symptoms.

Otherwise, the warm drink itself is probably doing much of the work rather than the other medicines in the drink.

Be careful you don’t accidentally double up on medicines in the drink and ones you might be taking as a tablet or syrup.

So what actually works?

Evidence supports the use of a common household product: Honey.

A large 2020 meta-analysis synthesised the findings of 14 studies on honey. It found honey reduces cough frequency and severity and soothes the throat, working just as well as – or better – than many cough medicines.

Warm fluids and steam inhalation can also help loosen mucus and moisturise the airways.

Keeping your vaccinations up to date can help reduce the risk of some causes of coughs. If you’re over 65 you’re now eligible to receive the pneumococcal vaccine.

Take-home message

The next time you’re awake in the middle of the night trying to find something to keep your barking cough at bay, take a moment to consider whether you’re dealing with a short-lived illness that simply needs soothing while your body heals, or a problem that needs medical attention.

You may find you get just as much comfort from the products in your kitchen as the ingredients in your medicine cabinet.

Jack Janetzki, lecturer in pharmacy and pharmacology, Adelaide University and Lauren Cortis, senior lecturer in pharmacy practice, Adelaide University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.