Chemotherapy, called chemo, uses one or more drugs to kill cancer cells. Each cell in our body works in a special way to keep us healthy. Cancer forms when a group of abnormal cells grow and spread out of control. They affect the way your body normally works. Chemo is used to kill the cancer cells. It is given for a set period of time--a three-week cycle for instance--by mouth, by needle into a muscle or skin, or by needle into a vein. The drugs travel through the bloodstream to the cancer cells.

Chemo drugs can:

• stop cancer cells from growing and spreading 
• control or slow the growth and spread of cancer cells 
• shrink the size of the cancer

There are about 50 kinds of drugs used in chemotherapy. Chemo may:

• cure the cancer 
• control the cancer for awhile 
• reduce the risk of cancer coming back 
• help cope with or cure cancer symptoms like pain

Side effectsChemo drugs are supposed to kill cancer cells, but they can also damage healthy cells such as hair and blood cells. Side effects vary depending on the type of chemo drugs and how the cancer is affecting your body. Most side effects go away after treatment ends.

Most common side effects are:

• feeling very tired 
• losing hair 
• low blood cell levels, such as anemia or neutropenia (low white cell count) 
• nausea 
• vomiting 
• sore mouth or sore throat 
• not feeling hungry or feeling very hungry 
• changes in how you feel about sex 
• changes in a woman's menstrual cycle 
• constipation 
• diarrhea 
• feeling numb or tingling in your hands or feet 
• pain