7 doctors weighed in:
How long could cannabis be detected in the body after use?
7 doctors weighed in

Dr. Robert Kwok
Pediatrics
4 doctors agree
In brief: Usually weeks
Studies find that marijuana can be detected in the blood up to 3 weeks, and in the urine up to 3 months, depending on the person, the amount used, and his frequency of smoking mj.
In frequent users, mj is detectable for a long time. With infrequent, occasional users, mj may be out of the body after a few days in some instances. Mj brownies are probably detectable for similar durations as smoking.

In brief: Usually weeks
Studies find that marijuana can be detected in the blood up to 3 weeks, and in the urine up to 3 months, depending on the person, the amount used, and his frequency of smoking mj.
In frequent users, mj is detectable for a long time. With infrequent, occasional users, mj may be out of the body after a few days in some instances. Mj brownies are probably detectable for similar durations as smoking.
Dr. Robert Kwok
Dr. Robert Kwok
Thank
Dr. Anthony Vertino
Clinical Psychology
In brief: 30 days by hair test
30 days usually by hair test. Urine tests - results may vary.

In brief: 30 days by hair test
30 days usually by hair test. Urine tests - results may vary.
Dr. Anthony Vertino
Dr. Anthony Vertino
Thank
Dr. Jeff Livingston
Obstetrics & Gynecology
In brief: 30 days
The byproducts of marijuana can be detected on a urine drug screen for about 30 days after last use.

In brief: 30 days
The byproducts of marijuana can be detected on a urine drug screen for about 30 days after last use.
Dr. Jeff Livingston
Dr. Jeff Livingston
Thank
Read more answers from doctors