We’ve all been laid low with sneezing, a runny or blocked nose, a sore or scratchy throat, cough, low-grade fever, headache and aches and pains. And while colds are less severe than true flu or influenza, they can still make you thoroughly miserable.

Usually a cold lasts no more than 10 days, but it can trigger asthma, ear infections, sinus infections and a cough, and some of these can add extra weeks of illness.

Also colds are expensive; every year they cost the nation millions of dollars in doctor visits, medications and time off work.

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So what helps with a cold? Unfortunately, the scientific evidence around cold remedies and preventive agents is frequently of poor quality, and results are inconsistent. Nonetheless, a review of 67 independent studies published in the Canadian Medical Association Journal earlier this year did come up with some key conclusions.

If you want to avoid a cold or to treat one once it strikes, here are some tips based on the review’s findings.

1. Zinc tablets

Ever wished there was a simple pill you could take to ward off a cold? Well you’ll be pleased to know there is one type of pill that has at least some evidence behind it: a zinc supplement.

Taking zinc is one of the best ways to reduce the likelihood of contracting a cold, according to the 2014 review. Although the evidence for cold prevention with zinc comes from studies involving only children, there is no biological reason why zinc would work only in children and not adults, the authors say.

Frustratingly though, it’s not clear exactly how zinc may help. Also no one knows the best dose, formulation or how long you should take it.

According to the School of Public Health at the University of California, Berkeley, lab tests have found that zinc in the mouth and throat can deactivate cold viruses, block them from adhering to the nasal membranes and/or stop them from replicating. The mineral may also have some anti-inflammatory and antioxidant effects.

But prolonged use of high dose zinc can be harmful, so the University’s advice if you want to try zinc lozenges is:

• Start as soon as you have symptoms and follow the dosing advice on the label
• Don’t take the lozenges for more than a week
• Don’t take them long-term to prevent colds

2. Hand hygiene

Low-tech, but probably more effective than zinc supplements, good hand hygiene is the best bet for preventing a cold, the review found. This includes the use of wipes, alcohol-based disinfectants and regular hand washing.

A thorough wash, lasting 40 to 60 seconds (including the drying), with lots of rubbing together of the hands is recommended. Children can be encouraged to sing the entire “Happy Birthday” song twice to make sure they wash their hands for long enough.

You’ll also lessen your chances of catching the flu if you keep your hands away from your face. That’s because any virus picked up from a contaminated surface (say, where someone’s sneezed) will find it easier to gain entry to your body if you deposit it on the moist skin lining your mouth, nose and eyes.

3. Pain-relieving medications

Once a cold takes hold though, products containing paracetamol have been found to decrease the severity of headaches, fever, sinus pain and muscle aches. Paracetamol is far and away the safest option for both children and adults – as long as you do not exceed the recommended daily dose as this can cause liver damage, says Professor Ric Day, a clinical pharmacologist at St Vincent’s Hospital in Sydney.

You’re most at risk of taking too much if you’re using multiple over-the-counter medications. Paracetamol is an active ingredients not only in tablets, capsules or syrups clearly marked as such, but it’s also contained in a range of other over-the-counter products that include a mixture of ingredients – for example in cold remedies that you can make into hot drinks or some hayfever/allergy medications. So always read the medicine’s product information so you can note the ingredients.

The recent review did find ibuprofen-based painkillers provided more effective relief from pain and fever, especially in children. However it’s worth noting that some medical experts question whether treating a fever is necessary or advisable. There’s some evidence reducing a fever might actually hinder your recovery from an infection.

4. Nasal sprays

The review found top cures for an incessant runny nose were nasal sprays and nasal decongestants containing ipratropium bromide. Be warned though, in 2009 the US Food and Drug Administration cautioned against the use of zinc-containing products in nasal sprays, including homeopathic preparations, because they were associated with a risk of permanent loss of smell.

5. Over-the-counter cough medicines

Over the counter medicines can help fight a cold. Photo: Shutterstock

Cough medicines containing antihistamines have been found to be moderately effective in the overall treatment of colds in adults and older children, but only when combined with decongestants (drugs that relieve a blocked nose) or pain relief drugs. But you may get a dry mouth or insomnia as a side effect. (Note: you should not give over-the-counter cough and cold medicines to infants and children under six years of age and only on medical advice in children aged six to 11.)

“It is strange that antihistamines alone do not work, whereas they do work when combined with decongestants,” said Dr Bruce Arroll from the University of Auckland, one of the authors of the 2014 review.

While there is some evidence that cough syrups containing expectorants (which loosen mucus, making it easier to cough up) or suppressants (which suppress the urge to cough) may reduce the intensity or frequency of a cough, they have no effect in reducing its duration.

“People pay the price because they want the minor benefit and that’s everyone choice,” says Professor Christine Jenkins, respiratory physician at Sydney’s Concord Hospital.

A cough syrup containing codeine may help you get a more peaceful night’s sleep, as the drug has a mildly sedative effect, she says. However, the idea that cough suppressants are harmful because they leave mucus in the body is nothing but “folklore”.

To relieve a cough in anyone over the age of one, honey is worth trying. Both the World Health Organisation and the American Academy of Pediatrics recommend it.

-ABC