Marijuana is actually the mixture the leaves, flowers, and seeds of the hemp plant. Though normally it is used a drug by drug addicts yet lot of countries are legalizing its use as a medicine. Its extract is found in painkillers and sleeping pills as it has got the characteristic of relaxing the nerves that relieve pain and also helps to cure insomnia.
In India marijuana has been used since the Vedic period, well before 2000 B.C. In the 'Atharvaveda' it is said that small doses marijuana(bhang) relieves anxiety. During that period the seeds and the leaves of the hemp plant were used to cure phlegm and diarrhea. As in 'Ayurveda' it is said to relieve pain when taken in small quantities, it is used in most of the painkillers manufactured in India. However, use of marijuana for a long time can damage a person's liver and lungs and also brain cells causing loss of memory. Therefore in 1961 the 'Single Convention of Narcotic drugs' declared the use of marijuana as illegal and clubbed it with hard drugs.
In 2015 at a medical conference held at Bengaluru the use of marijuana extract(oil) was advocated as it could cure cancer. Hence to what extent it can be used has to be decided by the medical council of doctors. Indiscriminate use of marijuana can be dangerous and cause health hazard. Thus it can be made legal only for medical use under the supervision of doctor or only if the doctor prescribes it.