Chemotherapy can cure cancer because it kills cells. It kills cancer cells and it can kill normal cells. Killing normal cells can cause some unpleasant side effects. The side effects vary from one drug to another for many reasons. Not all chemo drugs cause hair loss, for example.
Note that each chemotherapy agent or regimen has some side effects that are specific to it. Also, the actual side effects may vary a great deal from patient to patient.
The good news about these side effects is that there are ways to ease most of the symptoms. Sometimes, however, certain side effects can have long lasting or permanent effects. For example, certain chemotherapy drugs can result in infertility or the inability to father a child which may be permanent. Certain options such as sperm banking may be available. Please talk to your doctor or nurse about any concerns before starting chemotherapy.