There could be lots of different reasons why you feel sick, including the cancer itself and its treatment.
Get more information on why cancer itself could cause you to feel or be sick.
Some cancer treatments cause sickness. Find out why this might happen to you and what can be done to help you feel more comfortable.
Sickness can begin at different points before, during or after your treatment.
There are things other than cancer or cancer treatment that can make you feel sick.