The insurance company checks your system for drugs to verify the status of your health and find out if you are taking any legal or illegal drugs.
If you are taking prescription marijuana for a health issue, they want to know about that ailment. If you take it socially even where marijuana may be legal over the counter, they want to know about it.
Life insurance companies test for marijuana on larger amounts of life insurance, and on the smaller policies there is usually a question or two about any drug use.
If you die as a direct result of using marijuana, and you had checked the boxes no on your application for life insurance for questions about marijuana use, a claim on your life insurance may be denied, especially if it is illegal to use marijuana where you live.
The life insurance company may test for THC which is the active ingredient in marijuana. However, use of marijuana is now legal in some states like Colorado, so life insurance companies may have a different position of approval for coverage in states where it is legal.
Learn more about life insurance for marijuana smokers.