Federal and state laws concerning drug possession are quite complex; specifics vary according to the quantity and type of drug and are further complicated by differences in state regulations. Under both federal and state law, possession of an illegal controlled substance is a criminal offense; these substances include marijuana, cocaine, heroin, methamphetamines, LSD, ecstasy, and various club drugs. Furthermore, possession of certain chemicals needed for the cultivation or manufacturing of drugs is illegal, as is possession of drug accessories. If a large quantity of drugs is found on an individual, he or she may be charged with possession with intent to distribute; smaller quantities result in simple possession charges.
While the law is quite stringent and often unforgiving, there are certain exceptions. One defense is unwitting possession. This refers to instances in which an individual is found in possession of an illegal substance without being aware of it; the most common cases of this involve mail carriers. Some states, however, do not allow this defense, and the burden of proof is always on the defendant.