cannabis

Some Limitations of Previous Marijuana Research Unfortunately, much of what is known about the human pharmacology of smoked marijuana comes from experiments with plant material containing about 2 percent THC or less, or occasionally up to 4 percent THC. In addition, human experiments typically are done in laboratory settings where only one or two smoked doses were administered to relatively young, medically screened, healthy male volunteers well experienced with the effects of marijuana or female marijuana seeds. Females rarely participated in past marijuana research because of prohibitions (now removed) against their inclusion.