The nicotine will totally be gone within 1-3 days after your last using tobacco. In urine: The urine test normally can detect nicotine level within 3-4 days after the last time you use tobacco. However, if you often smoke or you are passive smokers, nicotine can stay for a period of 15 to 20 days in urine. After this period, no traces of toxic can be found in your urine. In saliva: Nicotine stays in your saliva up to 4 days. In hair: nicotine can stay in hair for months instead of for days.