Health Self-Care: A Complete Guide to When You Can Manage It Yourself — and When You Must Get Help

Red, amber, green: work out what to do in thirty seconds

Every guide on this site uses the same three-colour triage. The order matters: first ask “is there anything that cannot wait?”, then ask “how do I look after this?” Doing it the other way round is how people end up taking a risk they did not need to take.

The review deadline is part of green, not an optional extra. “Let us see how it goes” with no deadline turns into delay very easily, which is why every guide here states what would move you up a level.

You can open the Health Self-Care Assistant now, set your situation on the left, and read the triage that applies to you.

What is a “red flag”, and why does it come before everything else

A red flag is not a severe symptom — it is a symptom that cannot wait. The test is not how much it hurts or how frightening it looks, but: if this were that illness, would tomorrow be too late?

That is why the red-flag list here contains both frightening and unremarkable-looking entries. A sudden worst-ever headache is frightening; cold hands and feet, drowsiness and passing very little urine just look like tiredness, and all three can be signs of sepsis.

If you remember only one line: when you are not sure, phone and ask. 999 in Hong Kong and the UK, 119 in Taiwan, 120 in mainland China, 911 in North America — or your own doctor. Asking for help is cheap; delay is expensive.

Why ruling out danger beats guessing the diagnosis

Most people searching their symptoms are really asking “what illness do I have?”. That question almost never has a reliable answer online, and asking it first is what causes harm: once you assume “it is probably just gastroenteritis”, you start explaining away the evidence that does not fit.

Triage asks a different question: before any diagnosis, is there anything I have to do right now? That question is answerable without a diagnosis, and the answer is usually short — call an ambulance, get seen today, or it is reasonable to watch.

• It blocks confirmation bias. Listing what cannot wait before considering self-care stops a plausible guess from turning into a delay.
• It gives families an action. What a relative needs is not a disease name but the answer to “do we go to hospital now?”.
• It makes waiting safer. Both the amber and green instructions exist to stop things getting worse before you are seen.

Medical triage is the process of sorting people by how soon they need care, and it works before the diagnosis is known — which is exactly why it is useful to you at home.

This is the main difference between a self-care tool and a symptom checker: the safety net comes before the care advice.

It also means the useful question is not only “what is this?”, but “what would make this urgent?” Learning to recognise red flag symptoms takes a few minutes and changes what you do next.

Amber: get seen soon, but you do not need an ambulance

Amber is the level people skip, because it is “not urgent, but not something to leave”. It means: needs medical assessment, with no immediate threat to life. If you are looking for one rule for when to see a doctor rather than wait, this is that level: it needs assessing today.

• When: usually today or within 24 hours. If it appears at night, the next morning is often fine — but if you are unsure, phone and ask.
• What to do: write down what changes (times, temperature, how much they are eating and drinking, urine output, whether a rash is spreading). This is what a clinician most needs, and every guide here asks for it.
• What not to do: do not let “I will look at it tomorrow” carry an amber case into red-flag territory. Amber exists to stop that happening.

Examples of amber: a fever lasting more than 5 days (think Kawasaki disease), earache with fever, diarrhoea lasting more than 7 days, a child who has daytime wetting as well as bedwetting, or back pain that wakes you at night.

Green: three principles of self-care, and three common mistakes

Principle one: treat the symptoms, not a label. Green means “how to be more comfortable and how not to get worse” — not treating a diagnosis.

Principle two: set a review deadline. “Keep an eye on it” needs an end time and an upgrade condition. Every guide here says what would move you from green to amber, and from amber to red.

Principle three: fix the reversible things. Dehydration, constipation, too little sleep, smoking, alcohol and long periods of sitting look unremarkable, and they make almost everything harder to recover from.

The three most common mistakes:

• Using antipyretics to “treat” a fever. They exist to make a distressed person more comfortable; they do not prevent febrile seizures, and bringing a number down is not the goal.
• Letting one number decide whether to get help. Heatstroke is about mental state, sepsis may come with no fever at all (or a low temperature), and in a child over 6 months temperature alone must not be used to judge how ill they are.
• Mistaking “I have read about it” for “it is safe”. Research tells you which level to use; it does not change the illness. Getting worse means getting worse.

Five questions people ask most often

1. How high a fever means we should see a doctor?

Age matters more than the number. A temperature of 38°C or above under 3 months, or 39°C or above between 3 and 6 months, is high or intermediate risk and needs prompt assessment; over 6 months, do not judge by temperature alone. Also look at alertness, feeding, urine output, any rash, and how many days it has lasted — a fever beyond 5 days should raise Kawasaki disease.

2. When does chest pain mean calling an ambulance?

A crushing or heavy sensation, pain spreading to the arms, neck, jaw or back, with cold sweat, breathlessness or nausea — call an ambulance immediately. Do not drive yourself. Sit and rest while waiting; chew 300 mg aspirin if you have it and are not allergic. “It feels a bit better” is not a safe signal.

3. What should I do about a sudden severe headache?

If it came on suddenly and is the worst headache of your life, treat it as an emergency: go straight to the emergency department rather than waiting to see whether it settles or going to a GP first. NICE defines a thunderclap headache as one “typically peaking in intensity within 1 to 5 minutes”, but a headache that never peaked, or does not match the description, is not excluded by that.

4. A baby will not stop crying — how do I know if it is ill?

Crying is a normal developmental stage (peaking at 6 to 8 weeks and improving by 3 to 4 months). What needs assessing is a change in the cry: fever, clearly reduced feeding, no weight gain, green or projectile vomiting, a swollen tummy, floppiness, a weak or high-pitched cry, or no wet nappy for 8 hours. If you feel something is wrong, get them seen — parental instinct has real value in recognising serious illness in children.

5. Heatstroke or heat exhaustion?

The dividing line is mental state, not the thermometer. After heat exposure or strenuous activity, confusion, unsteady walking, a seizure or unconsciousness means heatstroke: call an ambulance and start cooling. Do not use sweating to decide — in exertional heatstroke the person is often still sweating heavily.

What this knowledge base contains (measured, not claimed)

This is not a chatbot and not a search engine. It is a structured knowledge base with a deterministic engine: you select your situation and symptoms, and fixed rules filter and order the content. These are the current measured figures — the test suite prints them on every run:

Coverage is a measurable threshold rather than an adjective: every self-care symptom must be covered, every emergency symptom must be intercepted, and every guide needs enough steps and categories. If any of that fails, the build fails.

What we base this on — and why the list is not longer

The rule is simple: we only write what we have actually read. Every guide and red flag names its organisations (NHS, NICE, WHO, CDC, Hong Kong's Department of Health, Taiwan's Ministry of Health and Welfare, and others), and an audit checks, entry by entry, that every claimed organisation can be traced back to the sources recorded for that entry. If it cannot, the build fails.

That rule has a cost, and we state it: a source we cannot read is a source we do not cite. NICE CKS returns HTTP 403 outside the UK and prohibits scraping, so it is never cited here; the American Heart Association's site returned 403 throughout the research, so our chest-pain entry does not quote it. Losing a big name is better than adding a citation nobody read.

Where authorities disagree, this site reports the disagreement instead of smoothing it over. The threshold for “this nosebleed will not stop”, for example, ranges from 5 to 30 minutes depending on the source; the numbers are listed, along with which one this site follows and why. Pretending the world agrees is more dangerous than admitting it does not.

What this tool does not do: four explicit limits

Health information that lists no limitations is implying it has none. These are ours, and they are not just legal boilerplate — they are things a reader will actually run into:

1. It is not a diagnostic tool and does not replace a doctor. It will not tell you what illness you have. It helps you decide which level to use right now.
2. It has not been individually reviewed by a clinician. The clinical_signoff field stands at 0 / 247 — that field exists precisely so we cannot pretend otherwise. Everything here should be read as organised public guidance, not as medical advice.
3. Not every entry has been individually re-checked yet. 60 of 247 entries have a review record (what was checked, what changed, which sources were used), and the rest are still at their initial version. Reviewing finds problems: so far, about nine in ten entries that have been re-checked needed changes — which is why the reviewing continues.
4. It gives no drug doses. Doses depend on age, weight, product concentration and liver and kidney function, so there is no universal number. Read the packet or ask a pharmacist; this site only says when something should and should not be used.

If you are in an emergency, stop reading this page and get help. 999 in Hong Kong and the UK, 119 in Taiwan, 120 in mainland China, 911 in North America, 000 in Australia.

Privacy and technology: why nothing is uploaded

The privacy question in health searching is concrete: you do not want “which symptoms I looked up” to become part of an advertising profile. The technical choices here are aimed at that:

• No AI generation. The content is written and structured by hand and the engine is fixed rules. No language model writes your answer, so there is no hallucination risk of that kind.
• No backend. The whole site is static files. No server receives your symptoms, and there are no accounts or logins.
• No tracking. No analytics, no advertising, no third-party fonts or CDNs — which also makes it faster and usable on a poor connection.
• Your answers stay on your device. What you select is kept in your browser's local storage, under your control.

It is completely free, with no paywall and no registration.

How to use it: three steps

1. Set your basic situation (age band, sex, existing conditions, lifestyle). This only filters which content is relevant to read; it is not a diagnosis.
2. Select your current symptoms, or search in plain words (in Chinese, "火燒心" for heartburn, "烙賽" for diarrhoea, "五十肩" for frozen shoulder). The list is re-ordered as you go.
3. Read the red flags before the self-care. If a red flag applies, the panel pins the emergency instruction to the top and locks the self-care content — at that point, follow it and stop reading.

There is no personal information to enter and no password to remember. Open the Health Self-Care Assistant now, or start at the OpusDesk Hub to see the other blocks.

Glossary

Red flag

A sign that cannot wait: if this were that illness, tomorrow could be too late. Self-care stops and you get help.

Amber

Needs medical assessment with no immediate threat to life — usually today or within 24 hours.

Green

Self-care and observation are reasonable, provided you set a review deadline and an upgrade condition.

Triage

Deciding which level to use before a diagnosis is known. That is what this site is for.

Health self-care

What can safely be done by yourself: symptom relief, fluids, rest, observation. It follows triage; it does not replace it.

Sources and further reading

These are the organisations this site's content actually draws on. Every guide and red flag lists which of them it used, and their public material is where the specific thresholds on this page come from:

• NHS (UK) — public guidance and thresholds for seeking care
• NICE (UK) — the guidelines themselves; the traffic-light system and most thresholds come from here
• WHO — oral rehydration salts, heat illness and public health
• CDC (US) — infection, occupational heat illness and child safety
• healthdirect (Australian government) — symptom triage and first aid
• Hong Kong Department of Health, Family Health Service — infant care and parent guidance
• Taiwan Ministry of Health and Welfare — child protection and public health
• Cochrane — systematic reviews, used to judge whether a treatment actually works

This page was last updated on 2026-09-15. Every entry in the knowledge base carries a next-review date, and an overdue review fails the build — that is how we slow the content rotting.

Frequently asked questions