Cover the basics: Include major illnesses or injuries, chronic diseases, hospitalizations, surgeries, allergic reactions, immunizations, screening tests and your blood type. Also list names and dosages of medicines and supplements (and check your spelling, because many have similar names).
But don't go overboard. You don't need to record minor illnesses such as colds or strep throat.
Go for dates: Whenever possible, include the date of events and new prescriptions. List both the admission and discharge date for hospital stays.
Research your family history: Find out as much as you can about diseases and causes of death for your parents, grandparents, siblings and aunts and uncles. Many illnesses have a genetic component.
Fill in holes: Ask your doctors' office for copies of past medical records and read back as far as you can.
Record your symptoms: If you have a long-term issue such as diabetes or chronic pain, write down blood sugar and pain readings and what was going on in your life at that moment. Your doctor may be able to spot patterns and recommend lifestyle changes rather than more medication.
Stay up to date: Add to your journal whenever you start a new medication, notice new symptoms or have a health emergency.
Bring your journal to your doctor: Carry it to all appointments, even routine ones.