Fact sheet: The common cold
Colds are a part of life. They are usually harmless and get better on their own within a week. But symptoms like coughing, a sore throat or a headache can be bothersome. This fact sheet describes what you can do to prevent colds, and what can help if you do come down with one.
What is a common cold exactly, and how is it different from the flu?
A common cold is an infection that develops over a few days. It is usually caused by a virus and generally begins with a sore or scratchy throat. Within a few days, more symptoms can start: a blocked or runny nose, sneezing, coughing and a headache. Sometimes people have a mild fever and feel weak too.Even though a cold can make you feel really sick, if you are otherwise healthy, a cold will mostly get a lot better by itself within a week. The worst is usually over within three or four days.
Colds are very common, especially in children. It is not unusual for a child to pick up a cold at school or childcare between six and ten times a year. In babies and small children, the cold can cross over from the throat to the ear, and cause a middle ear infection (acute otitis media). Adults get between two and four colds a year on average, usually in winter.
The types of virus that cause colds are basically different from those that cause the flu (influenza). The flu is usually associated with more severe symptoms than a cold. It can be hard to tell the difference, though, between a very bad cold and a mild case of the flu. You will find more detailed information about the flu in our feature “Influenza”.
The flu usually starts quite suddenly, with a high fever, shivering, achy joints and muscle ache. Flu hits faster, harder, and lasts longer than a cold.
It may be necessary to go to the doctor if
- you have a fever (body temperature over 38 degrees Celsius),
- your symptoms are severe or getting worse,
- you have pain, especially in your chest,
- you are having difficulties breathing,
- your symptoms do not get better within a week or so.
What are the symptoms of a cold?
The cold is an “upper respiratory tract infection” (URTI) – an infection of the nose and throat. Typical symptoms include a runny or blocked nose (rhinitis). Inflammation of the throat, causing a sore throat, is also common. This is called “pharyngitis”.
You can have other illnesses at the same time as a cold, such as:
- sinusitis: an infection of the sinuses (little spaces in the skull), which can cause headaches – you can read more about that in our feature on sinusitis;
- laryngitis: an infection of the voice box (larynx), which can make it hard to talk;
- tonsillitis: an infection of the tonsils, which are on either side of the throat;
- bronchitis or pneumonia: infections that affect the lower respiratory tract, which are caused by other types of germs than common colds are.
The above illnesses will not be discussed in more detail here because they may require special treatments.
What helps against colds?
The viruses that cause colds can quickly change over time, which means that having one cold does not protect you from colds in the future. That is also why there is no treatment or vaccination that directly affects these viruses.
Your body will generally fight off colds without needing any help. However, there are a number of remedies or medicines you can try out that could help relieve the symptoms and discomfort.
These include inhaling steam, bed rest and chest compresses, as well as taking zinc products or herbal remedies containing echinacea, for example. None of these remedies have been proven to work, though. There is only some evidence to suggest that certain echinacea products made from the coneflower called Echinacea purpurea may relieve the symptoms if they are taken at the beginning of a cold. You can read more about this in our research summary “Common colds: Does echinacea work?”.
Another drug that is very popular in Germany and is often used to treat respiratory infections is an extract from the root of Pelargonium, a certain kind of geranium plant. It is marketed in Germany under the names Umckaloabo or Kaloba. Researchers have found weak evidence that this herbal remedy might relieve the symptoms of respiratory tract infections and speed up recovery. But it can have adverse effects too, such as stomach and bowel problems. Moreover, the use of products containing Pelargonium root extract has been associated with individual cases of hepatitis (inflammation of the liver). You can find out more about this in our research summary “Acute respiratory tract infections: Can Umckaloabo or Kaloba relieve symptoms?”.
There is better evidence for drugs like acetaminophen(paracetamol) and acetylsalicylic acid (ASA, or ASS in German). Although they are not able to speed up recovery, they can at least relieve some symptoms, like a sore throat. Children should not take ASA, as it can cause a rare but dangerous side effect.
People are often advised to drink plenty of fluids if they have a cold. But this has not been scientifically proven to speed up recovery, at least not in children and teenagers. So there is no medical reason to drink more than feels comfortable when you have a cold.
Can antibiotics help?
Although many people believe that antibiotics work against all infections, this is not the case. They only fight infections that are caused by bacteria. They are powerless against viruses.
That is why antibiotics cannot usually do much against the common cold. Most colds are caused by viruses. Only in rare cases there is also bacterial infection, which can be caused by streptococcal bacteria (”strep throat”). Drugs for colds are being developed, but these are not yet ready for widespread use.
Antibiotics have not been shown to have a clear benefit in the treatment of simple colds. At the same time, about 1 in 10 people who take antibiotics will get adverse effects from the medication. The most common of these include diarrhea, nausea, vomiting, headaches, skin rashes and vaginal thrush (vaginitis).
If the runny or blocked nose is not better after about a week, an additional bacterial infection may have developed. If that is so, antibiotics are more likely to help. One sign of bacterial infection is if the mucus discharge from the nose is yellow or green.
Antibiotics are not very helpful against common sore throats either, with the exception of bacterial infections like strep throat. Sore throats also get better on their own within a week. Research has shown that, without treatment, symptoms of a sore throat will get better within three days in 4 out of 10 people. Antibiotics against strep throat increase this to about 6 out of 10 people. But here again, you need to take side effects into account.
Apart from the adverse effects, which can happen immediately, using antibiotics unnecessarily can cause other problems too: they may become less effective. For years now, it has been observed that many disease-causing bacteria are becoming increasingly resistant (unresponsive) to antibiotics. This means that a lot of medical conditions can no longer be treated as successfully as they used to be. You can read more about this topic in our feature “Using antibiotics”.
If your doctor does not think you need antibiotics for your cold, it is very likely to get a lot better on its own within a few days. You may be given a prescription just in case, so that you can use antibiotics if your symptoms have still not improved after a week. Even though we tend to pick up medications from the pharmacy earlier – particularly if it is your own child who is ill – it often makes sense to wait a bit first. You can read more about that in our research summary “Common colds: Wait before trying antibiotics?”. As we have already said: most colds are caused by viruses, and antibiotics do not work against viruses.
What about vitamin C?
Many people regularly take vitamin C tablets to prevent a cold, or take them when they have a cold to try to cure it. However, trials show that vitamin C can only in exceptional cases prevent the common cold. Taking vitamin C at the start of a cold does not relieve symptoms or shorten the illness. Taking very high doses of vitamin C every day can also cause side effects such as diarrhea. This can be a worse health problem than the cold, particularly for older people and young children. You can read more about this in the research summary “Common colds: Can vitamin C prevent or relieve them?”.
What can you do to limit the spread of colds?
The viruses that cause colds are spread to others from everything that has touched the mouth or nose of someone who has a cold. This includes cups the sick person has been drinking from, as well as their hands and, of course, used tissues and handkerchiefs. That is why it is important not to leave used tissues lying around in places where other people might come into contact with.
Every time a person with a cold sneezes or coughs, lots of tiny virus-containing droplets are sprayed into the air. If you touch something that these droplets have landed on, the viruses spread to your hands. If you then touch your nose or mouth, you can easily get infected. This means that keeping your hands away from your face could help reduce your chances of getting a cold. Washing your hands regularly with normal soap has been shown to be a very good way to prevent colds. You can read more about how you can limit the spread of colds in our information “Protecting yourself and your family from respiratory viruses”.
Author: Institute for Quality and Efficiency in Health Care (IQWiG)
Next planned update: July 2015. You can find out more about how our health information is updated in our text "Informed Health Online: How our information is produced".
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IQWiG health information is based on research in the international literature. We identify the most scientifically reliable knowledge currently available, particularly what are known as “systematic reviews”. These summarize and analyze the results of scientific research on the benefits and harms of treatments and other health care interventions. This helps medical professionals and people who are affected by the medical condition to weigh up the pros and cons. You can read more about systematic reviews and why these can provide the most trustworthy evidence about the state of knowledge in the category “Evidence-based medicine”. We also have our health information reviewed to ensure medical and scientific accuracy.
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