The homeostasis of human body is significantly disturbed when organs' work-relax periods are not harmonized. Intensive Care Unit (ICU) patient's circadian rhythm is almost inevitably upset as a result of their disease and/or medical intervention. There are numerous animal studies prove that circadian rhythm and periodic dynamics are directly related to healing time and hence, mortality rate. Although, one of the main messengers of circadian synchronization is melatonin, it is overridden by temperature, and a number of other factors from e.g. the digestive tract. If the circadian rhythm is disturbed, the function of different organ systems becomes desynchronized and chaotic.