Weed seems to be very beneficial to the brain indeed. But Marvelous, it also does kill brain cells. What people who use that as a reason to criticize weed don't know is it does that "killing" in a beneficial way. In lab tests and in human testing, weed kills glioma cells, which are dangerous brain cancer tumor cells. And it also aids a process called "apoptosis," which is basically the brain's (and body's) way of thinning or trimming out unnecessary or damaged cells that need to be destroyed in order for healthy cells to thrive. The brain-cell killing that occurs in regards to cannabis is quite beneficial.