Detoxification or "detox" is the process of allowing drugs in a patient's body to be processed by the patient's organs or, in some cases, by treating and replacing the patient's blood. It is usually used in the treatment of drug addiction. The major problems with detoxification is the speed of the process (it can take weeks for some drugs to be processed normally) and the withdrawal symptoms being suffered by the patient. These symptoms may mask other diseases being suffered by the patient.