Catherine, Princess of Wales, announced on Friday that she is undergoing preventative chemotherapy to treat cancer discovered after she had abdominal surgery.
While the exact situation is difficult to determine because the 42-year-old princess did not disclose the nature of the cancer, here is an explanation of preventative chemo.
Chemotherapy is the use of powerful drugs to stop cancerous cells from growing, dividing and creating more cells. There are a large number of kinds of chemotherapy, depending on the cancer, how far it has spread and the treatment regime.