text: does thc automatically stay in your system for at least one month? if so, how can i flush my system out?  can it stay in your system for only a few days? it depends on how much thc was used and for how long a period.  a small amount, one time, and you should be clean in a few days.  a moderate amount to larger amounts over a longer period of time, will result in significant quantities of thc being absorbed by the fat in your body.  the thc in the fat will then start leeching out over a period of time.  this process is commonly described as taking about a month to get rid of all of the absorbed thc.