Most coughs, sore throats and earaches are caused by viruses. Colds and 'flu are always caused by viruses. Other viruses can cause more serious illnesses e.g. measles, smallpox, AIDS. Fungi cause diseases like athlete's foot, thrush and ringworm. Bacteria can cause a number of illnesses e.g. tuberculosis, bronchitis, pneumonia, cystitis.
Your doctor may be able to tell you what type of bug , or microbe, is causing your illness. Many of the common infections, such as colds and coughs, are caused by viruses and cannot be treated successfully with prescription medicines such as antibiotics. Your doctor may not give you a prescription for a cough, cold, sore throat, 'flu or earache. See the individual sections on common illnesses for more details - choose a section from the middle menu on the left. When it is not obvious from your symptoms which type of bug is causing your illness your doctor may take a blood or urine sample and send it to the laboratory for testing. This will identify the organism causing the infection. Most infections clear up on their own and often the best course of action is to let nature take its course, although if you are worried about an infection you should see your health professional for medical advice.