Marijuana is a general name for a drug prepared from the herb Cannabis sativa. Delta-9-tetrahydrocannabinol (THC) is the key psyche-altering constituent in marijuana, but the plant contains additional four hundred other chemical ingredients. It is made from dried leaves of Cannabis sativa plant, and the quantity of THC in marijuana determines the potency of its effects. The weather, the diversity of plant, the harvesting time, the soil, and other conditions determine the potency and the strength of marijuana. The potency of marijuana used today is ten times better than cannabis used in the late 19th century. Marijuana of high potency increases the mental and physical effects, leading to possible heath complications to the consumers or drug users.