Marihuana makes up a good portion of the drugs the crime laboratory receives. The botanical name for marihuana is Cannabis. The portions of the plant typically used for abuse are the leaves and the flowering tops.

Historically, the plant was used as a source of fiber (hemp). Its seeds were a food source, and the plant itself had some rudimentary medicinal uses.

Today, outside a small market for hemp products, the plant has no recognized medicinal or industrial uses.

The Controlled Substances Act classifies marihuana as a Schedule I controlled substance.

Typically, the plant material is smoked, using either a pipe or a hand rolled cigarette. Manifestations of its use include euphoria, an altered sense of time, lack of motivation, and difficulty concentrating and forming concepts. In addition, psychological dependence is commonly associated with the use of marihuana.