How to keep a symptom diary your doctor will actually use
"How often does it happen?" "Is it getting worse?" "Did the new medication help?" Doctors ask questions like these at almost every appointment, and memory is a poor witness. A simple symptom diary turns vague impressions into facts you can both work with. Here's how to keep one that's quick to fill in and genuinely useful.
Why a diary helps
- It replaces guesswork. "About twice a week" becomes "9 bad days in the last 4 weeks".
- It reveals patterns. Symptoms that follow poor sleep, certain foods, stress or your cycle often only show up on paper.
- It shows whether treatment works. Comparing the weeks before and after a change is far more reliable than recall.
Headache clinics are a good example: NHS hospitals and charities such as The Migraine Trust routinely ask patients to keep a headache diary before appointments, because it helps with diagnosis, spotting triggers and checking treatment.
What to record
Keep it short. A 30-second entry you make every day beats a detailed form you abandon after a week. For each day, note:
- Date and time the symptom started, and roughly how long it lasted.
- What you felt, in your own words: pain, fatigue, nausea, dizziness, low mood.
- How bad it was, on a 0 to 10 scale, where 0 is none and 10 is the worst imaginable.
- Medication: what you took, the dose and the time.
- Possible factors: sleep, meals, alcohol, exercise, stress, your period, weather.
- A short note for anything unusual.
Record good days too. A diary that only covers bad days makes it impossible to count how often things happen.
How long to keep it
Aim for at least four weeks before an appointment, and longer if your symptoms come and go. Some clinics ask you to send your diary a few days in advance, so check what yours prefers.
Turning it into a one-page summary
Your doctor won't have time to read every entry. Bring a short summary instead:
- The period covered, for example "1 to 28 October".
- How many days you had symptoms, and how many were severe (7 or more out of 10).
- Any patterns you noticed, and any you're unsure about.
- What you took and whether it helped.
- The two or three questions you most want answered.
Keep the full diary to hand in case your doctor wants details.
Paper or app?
Paper is private and simple, but hard to summarize. Apps make charts and reports easy, but some send your entries to their servers, share data with third parties or lock key features behind subscriptions. If you use an app, check where your data is stored before you start. We cover what to look for in our guide to symptom tracker privacy.
Important: a diary helps you talk to your doctor; it doesn't replace medical advice. If you have sudden, severe or worrying symptoms, contact a doctor or emergency services straight away.