Ответ:

1. A bad one can wake you up! dream

2. You do this when you have hay fever. sneeze

3. This can be high when you have the flu. temperature

4. It can stop you eating some foods. allergy

5. You take it when you're ill. medicine

6. He/She looks after your teeth. dentist

7. This can hurt when you eat too quickly. stomach

8. Feeling well, not ill. healthy