Medical Japanese: 症状, 診断, 治療, 予防, 副作用

Core examples: 症状, 診断, 治療, 予防, 副作用, 発熱, 頭痛, 既往歴, アレルギー, 服用, 受診.

Medical Japanese turns discomfort into categories

A patient says, “I feel bad.” A medical form asks for:

症状 既往歴 アレルギー 服用中の薬 診断 治療 副作用

Medical Japanese organizes experience into institutional categories: symptoms, history, diagnosis, treatment, medication, risk, and follow-up.

The key principle is:

Medical vocabulary separates what the patient feels, what the clinician identifies, what treatment is done, and what risks must be watched.

This article is for language comprehension, not medical advice. In medical situations, rely on qualified healthcare professionals.

症状: symptoms

症状

means symptoms.

Examples:

症状がありますか。 Do you have symptoms?

症状が続く symptoms continue

主な症状 main symptoms

Common symptom words:

発熱 fever

頭痛 headache

咳 cough

のどの痛み sore throat

吐き気 nausea

Learner action: separate patient-reported symptoms from diagnosis.

診断: diagnosis

診断

means diagnosis.

Examples:

医師が診断する a doctor diagnoses

診断結果 diagnosis result

インフルエンザと診断された was diagnosed with influenza

Diagnosis is a professional judgment. Do not confuse symptom with diagnosis.

Example:

発熱 fever symptom

インフルエンザ possible diagnosis

治療: treatment

治療

means treatment.

Examples:

治療を受ける receive treatment

治療を開始する begin treatment

治療法 treatment method

Treatment may include medication, surgery, therapy, rest, monitoring, or other medical action.

予防: prevention

予防

means prevention.

Examples:

感染を予防する prevent infection

予防接種 vaccination/immunization

予防策 preventive measures

Public-health Japanese uses 予防 frequently. It belongs to risk reduction before illness occurs.

副作用: side effects

副作用

means side effect.

Examples:

副作用が出る side effects occur

主な副作用 main side effects

副作用が疑われる場合 if side effects are suspected

Medication labels and vaccine information often list 副作用. Read carefully and ask professionals when uncertain.

既往歴 and アレルギー

既往歴

means medical history/past illness history.

Forms may ask:

既往歴がありますか。 Do you have a medical history/past illnesses?

アレルギー

means allergy.

Forms may ask about:

薬のアレルギー drug allergies

食物アレルギー food allergies

Learner action: these fields matter. Do not leave them blank casually if relevant.

服用: taking medication

服用

means taking medicine.

Examples:

薬を服用する take medicine

服用中の薬 medicine currently being taken

1日3回服用してください take three times per day

Medication instructions may also use:

内服 oral medication

外用 external use

頓服 as-needed medication

Learner action: read dosage and timing carefully.

受診: seeing a doctor/medical consultation

受診

means receiving medical examination/consulting a medical institution.

Examples:

早めに受診してください。 Please see a doctor promptly.

受診歴 history of medical consultations

医療機関を受診する visit/consult a medical institution

受診 is more formal than 医者に行く.

Patient speech versus doctor-facing terms

A patient may say:

頭が痛いです。 My head hurts.

A form may say:

頭痛 headache

A doctor may say:

症状はいつからですか。 Since when have you had symptoms?

Medical Japanese often has everyday expressions and kango technical terms for the same thing.

Learner action: learn both patient-friendly and form-facing terms.

Example bank walkthrough

症状

Symptoms.

Learner action: patient experience category.

診断

Diagnosis.

Learner action: clinician’s identification.

治療

Treatment.

Learner action: medical intervention.

予防

Prevention.

Learner action: risk reduction before illness.

副作用

Side effects.

Learner action: read medication labels carefully.

発熱

Fever.

Learner action: symptom term common on forms.

頭痛

Headache.

Learner action: useful symptom word.

既往歴

Medical history.

Learner action: important on intake forms.

アレルギー

Allergy.

Learner action: list clearly if relevant.

服用

Taking medicine.

Learner action: check dosage instructions.

受診

Visit/consult a medical institution.

Learner action: formal term for seeking care.

Medical-reading routine

When reading medical Japanese:

1. Classify term: symptom, diagnosis, treatment, prevention, medication, warning?
2. Identify subject: patient, doctor, medication, disease?
3. Check time: current, past, ongoing, after taking medicine?
4. Check action: take, stop, consult, monitor, avoid?
5. Check risk language: 副作用, 注意, 禁忌, 相談.
6. Check dosage: amount, frequency, timing.
7. Use professional help for uncertainty.

Patient-facing versus professional terms

Medical Japanese often gives two versions of the same reality.

A clinic form may use the right column. A patient conversation may use the left column. Learners should be able to move both ways.

Warning language on labels

Medication and public-health notices often use compact warning words:

使用上の注意 precautions for use

服用しないでください do not take

医師に相談してください consult a doctor

ただちに受診してください seek medical care immediately

副作用が疑われる場合 if side effects are suspected

These are action instructions. Do not read them as passive information.

Time and dosage matter more than vocabulary glosses

A medication instruction may contain:

1日3回、食後に服用してください。

The critical information is frequency and timing:

• 1日3回: three times a day
• 食後: after meals
• 服用: take medicine

For medical reading, extract action, timing, amount, and warning before trying to polish translation.

This article is language guidance only; health decisions require qualified medical advice.

A strong tool for this article would help learners parse forms and labels.

Suggested functions:

1. Form annotator: 症状, 既往歴, アレルギー, 服用中.
2. Symptom mapper: patient phrase → medical term.
3. Medication instruction decoder: dosage, frequency, timing.
4. Warning highlighter: 副作用, 注意, 受診してください.
5. Patient/professional register labels.
6. Safety prompt: advise consulting a medical professional for real care.

Final rule

Medical Japanese classifies experience.

症状 are what you feel. 診断 is what is identified. 治療 is what is done. 予防 reduces risk. 副作用 warns about unwanted effects. 服用 tells how medicine is taken. 受診 tells you to seek care.

In health contexts, language precision matters. When stakes are real, get qualified help.