History of cannabis as a medicine: a review
História da cannabis como medicamento: uma revisão
Cannabis as a medicine was used before the Christian era in Asia, mainly in India. The introduction of cannabis in the Western
medicine occurred in the midst of the 19
century, reaching the climax in the last decade of that century, with the availability and
usage of cannabis extracts or tinctures. In the first decades of the 20
century, the Western medical use of cannabis significantly
decreased largely due to difficulties to obtain consistent results from batches of plant material of different potencies. The identification
of the chemical structure of cannabis components and the possibility of obtaining its pure constituents were related to a significant
increase in scientific interest in such plant, since 1965. This interest was renewed in the 1990’s with the description of cannabinoid
receptors and the identification of an endogenous cannabinoid system in the brain. A new and more consistent cycle of the use of
cannabis derivatives as medication begins, since treatment effectiveness and safety started to be scientifically proven.
Keywords: Cannabis; Cannabinoids; Tetrahydrocannabinol; History; Therapeutic uses
Antes da Era Cristã, a cannabis foi utilizada na Ásia como medicamento, com grande importância na Índia. A introdução da
cannabis na Medicina Ocidental ocorreu em meados do século XIX, atingindo o clímax na última década deste século, com a
disponibilidade e o uso de extratos e tinturas da cannabis. Nas primeiras décadas do século XX, o uso médico da cannabis no
Ocidente diminuiu significativamente, em grande parte pela dificuldade na obtenção de resultados consistentes de amostras da
planta com diferentes potências. A identificação da estrutura química de componentes da cannabis e a possibilidade de se obter
seus constituintes puros foram relacionadas a um aumento significativo no interesse científico pela planta, desde 1965. Este
interesse foi renovado nos anos 90, com a descrição dos receptores de canabinóides e a identificação de um sistema canabinóide
endógeno no cérebro. Usos terapêuticos. Um novo e mais consistente ciclo de uso dos derivados de cannabis como medicamento
começa, já que a sua eficácia e segurança no tratamento começam a estar cientificamente provados.
Descritores: Cannabis; Canabinóides; Tetraidrocanabinol; História; Usos terapêuticos
Department of Neurology, Psychiatry and Medical Psychology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo
(USP), São Paulo (SP), Brazil
Rev Bras Psiquiatr. 2006;28(2):153-7
Antonio Waldo Zuardi
Financing: Conselho Nacional de Desenvolvimento Científico e
Tecnológico (CNPq) - Grant 300775/2004-0 and Fundação de
Amparo à Pesquisa do Estado de São Paulo (FAPESP) -
Conflict of interests: None
Submitted: 4 October 2005
Accepted: 21 November 2005
Antonio Waldo Zuardi
Av. Candido Pereira Lima 745 – Jd. Recreio
14040-250 Ribeirão Preto, SP, Brazil
Rev Bras Psiquiatr. 2006;28(2):153-7
History of cannabis as a medicine 154
Before the Christian Era
Cannabis Sativa (cannabis) is among the earliest plants
cultivated by man. The first evidence of the use of cannabis
was found in China, where archeological and historical findings
indicate that that plant was cultivated for fibers since 4.000
With the fibers obtained from the cannabis stems, the
Chinese manufactured strings, ropes, textiles, and even paper.
Textiles and paper made from cannabis were found in the
tomb of Emperor Wu (104-87 B.C.), of the Han dynasty.
The Chinese also used cannabis fruits as food. These fruits
are small (3 to 5 mm), elliptic, smooth, with a hard shell,
and contain one single seed. The first evidence of the use of
these seeds was found during the Han dynasty (206 B.C. -
220 A.D.). In the beginning of the Christian Era, with the
introduction of new cultures, cannabis was no longer an
important food in China, although, until today, the seeds are
still used for making kitchen oil in Nepal.
The use of cannabis as a medicine by ancient Chinese was
reported in the world’s oldest pharmacopoeia, the pen-ts’ao
ching which was compiled in the first century of this Era, but
based on oral traditions passed down from the time of Emperor
Shen-Nung, who lived during the years 2.700 B.C. Indications
for the use of cannabis included: rheumatic pain, intestinal
constipation, disorders of the female reproductive system,
malaria, and others.
In the beginning of the Christian Era,
Hua T’o, the founder of Chinese surgery (A.D. 110 – 207),
used a compound of the plant, taken with wine, to anesthetize
patients during surgical operations.
The Chinese used mainly the seeds of cannabis for medical
therefore, it may be assumed that they were referring
to that part of the plant when describing its medicinal
properties. Until today, cannabis seeds continue to be used as
a laxative by Chinese physicians.
It is acknowledged that the
seeds are practically deficient in Δ
THC), which is considered the plant’s main active constituent,
and is mainly composed of essential fatty acids and proteins.
Today some of these fatty acids are considered as having
therapeutic effects, such as the γ-linoleic acid, whose topical
use is recommended for eczema and psoriasis, and its oral
use for atherosclerosis, osteoporosis, rheumatoid arthritis, and
other inflammatory diseases.
In China, the medical use of
cannabis never reached the importance it did in India.
The first reference to the use of cannabis, as a
psychoactive drug, is also in the pen-ts’ao ching, as observed
in one of its phrases: ...ma-fen (the fruit of cannabis)... if
taken in excess will produce visions of devils … over a
long term, it makes one communicate with spirits and
lightens one’s body…
In spite of this reference, there are
scarce citations of the use of cannabis as a hallucinogen
in ancient Chinese texts. One possible explanation is that
such use was probably associated to shamanism, a religion
of the people from Central Asia. During the Han dynasty,
this religious practice started to decline in China, and
became disbelieved and increasingly restricted. Ancient texts
rarely mentioned shamanism and, thus, there is no reference
to the use of cannabis as a hallucinogen.
shamanism became gradually more restricted in China, it
was rather common in the Northern nomadic tribes, which
may have contributed to the dissemination of cannabis in
Central and Western Asia and in India.
In India, the use of cannabis was widely disseminated, both
as a medicine and as a recreational drug. Such a broad use
may be due to the fact that cannabis maintained a straight
association with religion, which assigned sacred virtues to
the plant. The Atharva Veda (a collection of sacred texts of
unknown author) mentions cannabis as one of five sacred
plants, referring to it as a source of happiness, donator of joy
and bringer of freedom. Hence, cannabis use became part of
numerous religious rituals in that region.
The plant’s psychoactive effects were well-known in India,
possibly due to the way it was prepared for use, which included
at least three preparations. The weakest type, Bhang, consists
of dry leaves from which flowers are carefully removed. A
stronger type, Ganja, is prepared with the female-plant’s
flowers. The strongest of them all is the Charas, made
exclusively of the resin that covers female flowers.
of preparation guarantee the presence of active cannabinoids.
Currently we know that the plant has secreting hairs that are
located mainly on the female-plant’s flowers and, in a smaller
amount, on the leaves of its superior third. Solitary resin glands
most often form at the tips of the trichome stalks. These glands
have a considerable amount of active cannabinoids. Breaking
the glands liberates the active cannabinoids.
In India, the medical and religious use of cannabis probably
began together around 1000 years B.C.
The plant was used
for innumerous functions, such as: analgesic (neuralgia,
headache, toothache), anticonvulsant (epilepsy, tetanus,
rabies), hypnotic, tranquilizer (anxiety, mania, hysteria),
anesthetic, anti-inflammatory (rheumatism and other
inflammatory diseases), antibiotic (topical use on skin
infections, erysipelas, tuberculosis), antiparasite (internal and
external worms), antispasmodic (colic, diarrhea), digestive,
appetite stimulant, diuretic, aphrodisiac or anaphrodisiac,
antitussive and expectorant (bronchitis, asthma).
Furthermore, cannabis was traditionally considered sacred
in Tibet, although little has been written about its religious or
medicinal use. In Tantric Buddhism, which was developed in
the Himalayas, cannabis was used to facilitate meditation.
Though seldom reported, it is believed that the medical use of
cannabis in Tibet was intense due to the following reasons:
the concepts of Tibetan medicine stem from Hindi medicine;
botany was of great importance in its pharmacopoeia; and,
finally, cannabis was abundant in that region.
Evidence suggests that the Assyrians also knew about the
psychoactive effects of cannabis and used it as incense since
the ninth century B.C.
It is also possible that, before the
Christian Era, Assyrians used the plant externally for swellings
and bruises, and internally for depression, impotence,
arthritis, kidney stones, ‘female ailment’, and for the
‘annulment of witchcraft’.
In Persia, cannabis was also known before the Christian
The Persians knew about the plants biphasic effect, and
made a clear distinction between its initial euphoric and its
late dysphoric effects.
In Europe, historical and archeological evidence suggests
the presence of cannabis before the Christian Era. It seems
the plant was brought by Scythian invaders, who originated
from Central Asian and reached close to the Mediterranean.
In the year 450 B.C., Herodotus described a Scythian funeral
ceremony, and stated that they inhaled the vapors obtained
from burning cannabis seeds with ritualistic and euphoric
purposes. That description was later confirmed by archeologists
who found charred cannabis seeds in Scythian tombs in Siberia
Reference to the use of cannabis by the Greeks and the
Romans are scarce, suggesting that it was little used by these
155 Zuardi AW
Rev Bras Psiquiatr. 2006;28(2):153-7
In the beginning of the Christian Era, there are two
references of the use of the seed’s juice for earache and to
drive worms and insects out of the ears.
Beginning of the Christian Era to the 18
In this period, the medical use of cannabis remained very
intense in India and was then spread to the Middle East and
Africa. In Arabia, well-known physicians mentioned cannabis
in their medical compendiums, as Avicena, in the year 1000
Muslim texts mention the use of cannabis as a diuretic,
digestive, anti-flatulent, ‘to clean the brain’, and to soothe
pain of the ears. In 1464, Ibn al-Badri reported that the
epileptic son of the caliph’s chamberlain was treated with the
plant’s resin, and stated: it (cannabis) cured him completely,
but he became an addict who could not for a moment be
without the drug’.
Cannabis is known in Africa at least since the 15
and its use was, possibly, introduced by Arab traders,
somehow connected to India. This is evidenced by the
similarity of the terms used for preparing the plant in Africa
and India. In Africa, the plant was used for snake bite, to
facilitate childbirth, malaria, fever, blood poisoning, anthrax,
asthma, and dysentery.
In the Americas, the use of cannabis probably began in
South America. In the 16
century, the plant’s seeds reached
Brazil; brought by African slaves, especially those from Ango-
la, and its use was considerably common among Blacks in
the Northeastern rural area. Most synonyms for cannabis in
Brazil (maconha, diamba, liamba, and others) have their origin
in the Angolan language. There are reports of the use of
cannabis in that region’s popular religious rituals, especially
the ‘Catimbó’, which includes cult to African deities and pre-
sumes the value of the plant for magical practice and treatment
of diseases. In the rural environment, there are reports of the
use of cannabis for toothache and menstrual cramps.
In Europe, during this period, cannabis was cultivated
exclusively for fibers. Muslims introduced the manufacture
ofpaper from cannabis, in 1150, first in Spain then in Italy.
Cannabis descriptions are found in many books about plants
written in this period, which clearly state, since the mid 18
century, the distinction between male and female plants
(previously described in a Chinese ideogram in the beginning
of the Christian Era).
References to the medical use of
cannabis are scarce. Europeans may have known about the
plant’s medical use in the Middle East and Africa, but they
confused it with opium.
Western medicine in the 19
There are some reports, from the early 19
the use of cannabis by European physicians, especially
regarding the use of the seeds or homeopathic medications.
However, the effective introduction of cannabis in Western
medicine occurred in the midst 19
century through the works
of Willian B. O’Shaughnessy, an Irish physician, and by the
book by Jacques-Joseph Moreau, a French psychiatrist.
O’Shaughnessy served in India with the British for several
years and made his first contact with cannabis use in that
country. He studied the literature on the plant, described many
popular preparations, evaluated its toxicity in animals, and,
later, he tested its effect on patients with different pathologies.
In 1839, he published the work: ‘On the preparations of the
Indian hemp, or gunjah’, which, in the first paragraph,
establishes a panorama of plant use:
‘The narcotic effects of Hemp are popularly known in the
south of Africa, South America, Turkey, Egypt, Middle East
Asia, India, and the adjacent territories of the Malays, Burmese,
and Siamese. In all these countries, Hemp is used in various
forms, by the dissipated and depraved, as the ready agent of a
pleasing intoxication. In the popular medicine of these nations,
we find it extensively employed for a multitude of affections.
But in Western Europe, its use either as a stimulant or as a
remedy is equally unknown’.
In his book, O’Shaughnessy describes various successful
human experiments using cannabis preparations for
rheumatism, convulsions, and mainly for muscular spasms of
tetanus and rabies.
Moreau used cannabis with a different purpose. He was an
assistant physician at the Charenton Asylum, near Paris, and
a common therapeutic practice at the time was to accompany
psychiatric patients in long trips to exotic and distant countries.
During those trips he observed that the use of hashish
(cannabis resin) was very common among Arabs, and he was
impressed with the substance’s surprising effects. In Paris,
around 1840, Moreau decided to experiment, systematically,
different cannabis preparations; first on himself and later on
his students. As an outcome, in 1845 he published the book
‘Du Hachisch et de l’Alienation Mentale: Etudes
Psychologiques’, with one of the most complete descriptions
of the acute effects of cannabis.
Moreau clearly states his
purpose: ‘...I saw in hashish, more specifically in its effects
on mental abilities, a powerful and unique method to
investigate the genesis of mental illness’.
These two types of medical interest for cannabis, concerning
its psychoactive effects (as an experimental psychotomimetic)
as well as its therapeutic use, persisted through the years.
O’Shaughnessy and Moreau’s contributions had a great impact
on Western medicine, especially due to the scarcity of
therapeutic options for infectious diseases such as rabies, cholera,
and tetanus. The medical use of the drug spread from England
and France reaching all Europe and then North America. In
1860, the first clinical conference about cannabis took place
in America, organized by the Ohio State Medical Society.
In the second half of the 19
century, over 100 scientific
articles were published in Europe and the United States about
the therapeutic value of cannabis.
The climax of the medical
use of cannabis by Western medicine occurred in the late 19
and early 20
century. Various laboratories marketed cannabis
extracts or tinctures, such as Merck (Germany), Burroughs-
Wellcome (England), Bristol-Meyers Squibb (United States),
Parke-Davis (United States), and Eli Lilly (United States).
The medical indications of cannabis, in the beginning of
century, were summarized in Sajous’s Analytic
Cyclopedia of Practical Medicine (1924) in three areas:
1) Sedative or Hypnotic: in insomnia, senile insomnia,
melancholia, mania, delirium tremens, chorea, tetanus,
rabies, hay fever, bronchitis, pulmonary tuberculosis, coughs,
paralysis agitans, exophtalmic goiter, spasm of the bladder,
2) Analgesic: in headaches, migraine, eye-strain,
menopause, brain tumors, tic douloureux, neuralgia, gastric
ulcer, gastralgia (indigestion), tabes, multiple neuritis, pain
not due to lesions, uterine disturbances, dysmenorrhea,
chronic inflammation, menorrhagia, impending abortion,
postpartum hemorrhage, acute rheumatism, eczema, senile
pruritus, tingling, formication and numbness of gout, and for
relief of dental pain.
Rev Bras Psiquiatr. 2006;28(2):153-7
History of cannabis as a medicine 156
3) Other uses: to improve appetite and digestion, for the
‘pronounced anorexia following exhausting diseases’, gastric
neuroses, dyspepsia, diarrhea, dysentery, cholera, nephritis,
hematuria, diabetes mellitus, cardiac palpitation, vertigo, se-
xual atony in the female, and impotence in the male.
Figure 1 shows an illustration of the periods in which the
medical uses of cannabis began in different regions.
In the second half of the 20
century, cannabis reached
great social importance due to the explosion of its consumption
for hedonistic purposes. Until that time, in the West, the
hedonistic use of the plant was limited to small groups. In
Europe, groups of intellectuals gathered to use the drug.
Descriptions of this use may be found in novels by 20
French writers, such as Gautier and Boudelaire. In the
Americas, this practice was relatively common among the Black
in the rural area of Northeastern Brazil since the 16
who would meet on weekends to use the drug in groups. This
use was later passed on to fishermen of the San Francisco
River and by sea to the coastal cities. In the early 20
the use of cannabis in Brazil remained restricted to small
low-socioeconomic groups, and was known as the ‘opium of
In Mexico, cannabis was also used by the most
underprivileged population and it was through Mexican
immigrants that its use, for recreation, reached the United
States in the first decades of the 20
century. Until the 1950’s,
in the United States, cannabis use was restricted to the
neighborhoods of Blacks and Hispanic immigrants.
Since the 1960’s, the recreational use of cannabis rapidly
spread among the younger ranges of the population throughout
the Western world. In the United States, the percentage of
young adults that had used cannabis, at least once, went
from 5%, in 1967, to 44%, 49%, 68%, and 64%, in 1971,
1975, 1980, and 1982, respectively.
This use remains
high until today.
In 1964, the chemical structure of Δ
THC was identified by Gaoni and Mechoulam,
contributed to a proliferation of studies about the active
constituents of cannabis.
The startling boost in cannabis consumption, which intensified
its social importance, along with the better knowledge of its
chemical composition (which made it possible to obtain its pure
constituents) contributed to a significant increase in scientific
interest for cannabis, as of 1965. The number of publications
about cannabis reached their peak in the early 1970’s. In this
period, a Brazilian research group, led by Carlini, had a great
contribution, especially about the interactions of Δ
Since then, Carlini has been developing
efforts for the realignment of public policies concerning cannabis
After the middle of 1970’s, the number of publications
started to slowly decline during the following two decades. The
interest in studies about cannabis was renewed in the early
1990’s, with the description and cloning of specific receptors for
the cannabinoids in the nervous system and the subsequent
isolation of anandamide, an endogenous cannabinoid.
Afterwards, the number of publications about cannabis has been
continuously growing, attesting the great interest in research
involving the herb. Figure 2 shows the evolution of the number
of publications about cannabis in the last 50 years.
With the growth of scientific interest for cannabis, its
therapeutic effects are being once again studied, this time
using more accurate scientific methods. There are studies, in
different phases, about the therapeutic effects of Δ
conditions such as: epilepsy, insomnia, vomits, spasms, pain,
glaucoma, asthma, inappetence, Tourette syndrome, and
others. Among the therapeutic indications of Δ
following are considered close to being proven: anti-emetic,
stimulant of appetite, analgesic, and in symptoms of Multiple
Other cannabinoids are also under investigation,
such as Canabidiol (CBD), which has evidence for therapeutic
effects in epilepsy, insomnia, anxiety, inflammations, brain
damage (as a neuroprotector), psychoses, and others.
Decline and rediscovery
In the first decades of the 20
century, the Western medical
use of cannabis significantly decreased. This may have
occurred, among other factors, because of the difficulty to
obtain replicable effects, due to the extreme varying efficacy
of different samples of the plant. At that time, the active
principle of cannabis had not yet been isolated and the drug
was used in the form of tinctures or extracts whose power
was dependent on different factors, such as origin, age, and
mode of preparation.
In addition, various medications appeared
at the end of the 19
century, with known efficacy for the
treatment of the main indications of cannabis. Vaccines were
developed for various infectious diseases, such as tetanus;
effective analgesics such as aspirin appeared , and hypodermic
syringes allowed the injectable use of morphine; and, as a
narcotic and sedative, cannabis was rivaled by substances
such as chloral hydrate, paraldehyde, and barbiturates.
Finally, many legal restrictions limited the medical use and
experimentation of cannabis. In the United States, as the result
of a campaign of the Federal Bureau of Narcotics, the
Marihuana Tax Act law was passed in 1937. Under this Act,
anyone using the plant was required to register and pay a tax
of a dollar an ounce (28.35 g), for medical purposes, and
100 dollars an ounce for any other use. Despite the low value
for medical use, the non-payment of this tax, however, resulted
in a 2.000 dollar fine and/or 5 years imprisonment. This law
brought difficulties for the use of the plant due to the excessive
paperwork and the risk of severe punishment. When cannabis
transaction regulations, including prescriptions, were
transferred to the tribute area, this law circumvented a decision
of the Supreme Court which gave the States the right to control
commercial transactions and, in practice, meant banning the
use of cannabis in the whole American territory. Cannabis
was removed from the American pharmacopoeia in 1941.
Figure 1 - Age of the beginning of cannabis use as a
157 Zuardi AW
Rev Bras Psiquiatr. 2006;28(2):153-7
However, cannabis products must be used cautiously since
some studies suggest that early-onset cannabis use can induce
cognitive deficits and apparently acts as a risk factor for the
onset of psychosis among vulnerable youths.
At the beginning of 2005, a multinational pharmaceutical
laboratory received the approval in Canada, and is pleading
authorization in the United Kingdom and the European Union,
to market a medication containing Δ
-THC and CBD for the
relief of neuropathic pain in patients with multiple sclerosis.
Thus, a new cycle begins for the use of cannabis derivatives
as medication, this time more consistently than in the past.
The structures of chemical compounds derived from cannabis
are now known, the mechanisms of their action in the nervous
system are being elucidated with the discovery of an
endogenous cannabinoid system, and treatment effectiveness
and safety are being scientifically proven.
Antonio Waldo Zuardi is recipient of National Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq) and was supported
in part by the Fundação de Amparo à Pesquisa do Estado de São Paulo
Figure 2 - Number of cannabis-related publications in the
last 50 years. The source used was the ‘ISI Web of Knowledge’
with the keywords: cannabis or marijuana or marihuana.
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