The way we live – travelling all over the place, congregating in cities – is a boon to respiratory viruses, providing them with ample opportunity to leap from one mucous membrane to another. There isn’t a cure or vaccine for the common cold and it’s highly unlikely either will be developed in the course of our lifetime. Countless products to relieve the symptoms are on the market, but do any of them work?

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The common cold is often caused by rhinoviruses. There are usually 100 different types of them out there – some say twice that – so although you might develop antibodies in response to one, that won’t stop you falling prey to another. By contrast, there are usually only four flu viruses circulating in any season.

Women have more immunity to the common cold than men, which is thought to be because of hormonal differences – after age 50, men and women have similar immunity levels. Until recently, it was thought people were more likely to get colds in winter because that’s when we tend to congregate indoors, and it had nothing to do with the temperature. However, more recent research suggests our immune systems are more likely to be depressed in winter, and also that rhinoviruses thrive in colder conditions.

Painkillers such as aspirin, paracetamol and ibuprofen might palliate such pain-related symptoms as headaches, sinus pain, sore throat and aching muscles. Nasal sprays with xylometazoline or oxymetazoline can help unblock your nose by making your inflamed nasal veins contract. This can be particularly useful when you’re trying to get a good night’s sleep, which helps you fight a cold. Antihistamines might help with the sneezing and the runny nose, but they can also have a sedative effect, so are best taken at bedtime.

The Common Cold Centre at Cardiff University notes that essential oils such as menthol and eucalyptus have been used for hundreds of years in the treatment of the common cold, and the tradition shouldn’t be dismissed. Menthol found in some plants, for instance, protects against predators by anaesthetising them – similarly, lozenges with menthol may relieve a sore throat by acting as a kind of local anaesthetic. Menthol won’t open up the nose in the way a nasal spray does, but it will make your nose feel cooler and clearer – the centre recommends this over sprays for young children.

Things get trickier when it comes to cough syrups. Most aren’t recommended for children under six, as there’s not much evidence that they are particularly effective and some good evidence that they could cause harm in this age group.

If used as recommended, they aren’t likely to harm adults, but there isn’t much evidence they’ll be that useful, either. This might not be because they don’t work or don’t work for some people, but because there’s no need to fork out the money to do the very expensive trials to prove that they do – countless people have been using them for decades and will probably continue to do so.

But you’d be better off knowing what you’re asking for. Cough medicines can be divided into two main categories: those aimed at a dry, tickly cough and those aimed at a chesty or, if you prefer, “productive” cough.

The former are sometimes called antitussives and work (theoretically) by suppressing the urge to cough, and typically include dextromethorphan and pholcodine. (Pholcodine is a weak opioid, and morphine-like drugs have long been known to be effective at suppressing airway reflexes.)

Cough syrups aimed at productive coughs are commonly called expectorants, and are designed to loosen mucus in the respiratory tract. They typically include guaifenesin, although a Cochrane Collaboration meta-analysis has concluded that there isn’t enough high-quality clinical data to prove or disprove the effectiveness of products that contain it.

According to the Common Cold Centre, a hot drink is just as likely to soothe a sore throat and calm a cough, particularly those containing slightly bitter flavours such as lemon. And spicy food, such as those containing horseradish or fresh chillies, will help clear congested air passages.

Some cough medicines combine an antitussive with an expectorant, but as Medsafe points out on its website, this is an “illogical combination”. Why would you want to loosen the mucus, only to suppress the urge to get rid of it? Sometimes, coughing is nature’s remedy.

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