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At the first signs of a cold, is over-the-counter medicine enough? When should I see a doctor?

This answer is a draft. It stays unpublished until legal review and source verification are complete.

The answerThe great majority of colds (common cold syndrome) are caused by viruses, and antibiotics (antibacterial drugs) do not work on them. Over-the-counter (OTC) cold medicines only "ease the symptoms"; there is basically no medicine that makes the cold itself end sooner. Rest, fluids and sleep are the core. Use OTC medicine "to make hard symptoms lighter so you can rest". However, see a doctor if you have a fever of 38.5°C (101.3°F) or above for 3 days or more, feel breathless, cannot take fluids, or your symptoms keep worsening beyond a week, and if you are an older person, an infant or someone with a chronic illness. Also take care: combining a combination cold medicine with a fever reducer easily doubles up ingredients such as acetaminophen (paracetamol).

A scratchy throat, a runny nose, a slight fever. When people in Japan think "this might be a cold", most wait it out with a "combination cold medicine" (総合感冒薬, sōgō kanbōyaku) from the drugstore (Matsumoto Kiyoshi, Welcia, etc.). That is often perfectly fine. But some behaviour is clearly best avoided, such as going to a clinic to ask for antibiotics, or stacking several medicines on top of each other.

What OTC medicine can and cannot do

ItemContent
Cause of coldsAround 90% viruses (rhinovirus, coronavirus, RS virus and others — over 200 types). Bacterial causes are a minority
Antibiotics (antibacterial drugs)Do not work on viruses. The Ministry of Health, Labour and Welfare's *Manual of Antimicrobial Stewardship* recommends not prescribing antibiotics for an ordinary cold. Unnecessary use increases resistant bacteria
Combination cold medicine (OTC)A mix of several ingredients: fever and pain relief, runny-nose relief, cough suppressant and so on. Eases symptoms, but there is no evidence it shortens the illness
Overlapping ingredientsTaking a combination cold medicine plus a fever reducer plus a painkiller easily doubles up acetaminophen or ibuprofen. For OTC acetaminophen, the guide is up to 900 mg a day (follow the product label)
CourseMost peak within 3–7 days and ease by about 10 days. A cough alone can linger 2–3 weeks
When to see a doctor38.5°C or above for 3 days or more, breathlessness or chest pain, unable to take fluids, worsening after more than a week, severe headache or stiff neck, older people, infants, pregnant women, chronic illness (diabetes, heart, lung or kidney)
[Verify] Check the wording of the latest edition of the *Manual of Antimicrobial Stewardship* (3rd edition, 2023) and the upper dose limit for OTC acetaminophen before publication.

Misunderstanding 1|Take antibiotics early and it clears up faster

Almost all colds are caused by viruses, and antibiotics do not work on them. Unnecessary use only adds the risks of side effects and resistant bacteria. A doctor who does not prescribe them is making the right call.

Misunderstanding 2|OTC cold medicine ends a cold sooner

OTC medicine only eases the symptoms; the length of the cold basically does not change. It is a tool for "feeling more comfortable so you can rest".

Misunderstanding 3|A fever should be brought down straight away

A fever is a sign that your immune system is working, and there is no need to force it down. Use a fever reducer when you feel bad or cannot sleep, and keep to the dose.

Misunderstanding 4|Cold medicine plus a fever reducer works better

The same ingredients overlap, raising the risk of strain on the liver and stomach side effects. Check with a pharmacist before combining them.

Misunderstanding 5|If it has not gone after a week, I just have a weak constitution

Worsening after more than a week, or a high fever that persists, may mean bacterial sinusitis, pneumonia or a different illness. Check whether you meet the criteria for seeing a doctor.

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Sources

https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000120172.html

https://www.jrs.or.jp/citizen/disease/

https://kakarikata.mhlw.go.jp/

⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.

About this article

What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.

This is general information. Results vary from person to person and depend on your own conditions and surroundings.

Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.

This article is not meant to diagnose or manage any specific medical condition. If you are worried about your health, see a doctor rather than relying on your own judgement.

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