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Distinguishing features
Marijuana is an annual herb 6-10 feet tall with palmately compound
leaves; leaflets are narrow, long, and coarsely serrate; flowers are
small and green in clusters in the axils of the upper leaves; marijuana is
dioecious.
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| Description. An
annual plant growing to 6 feet in height. The stem is erect and
multibranched. Palmate leaves are opposite toward the base and
alternate at the top, with 5-11 leaflets each. Male and female
flowers grow on separate plants and are greenish-white. |
| Geographic range.
Grows across the United States in most soil
types. Often found in soils, as well as in illegal
cultivation. Cannabis is a common roadside weed in the midwestern
United States. |
| Toxic principle.
More than 60 cannabinoid compounds have been
isolated from C. sativa. Tetrahydrocanibinol (THC) is the
compound most toxic to the nervous system. |
| Toxicity. Animals
are rarely poisoned because of the low palatability of the plant.
However, cattle, horses, pigs, ferrets, and dogs are susceptible to
intoxication after exposure. THC concentrations are highest in
flowers and leaves. |
| Mechanism of toxicologic
damage. Cannabinoids are rapidly
absorbed from smoke and more slowly absorbed post-ingestion. They
are rapidly metabolized by the mixed-function oxidase system in the
liver. Toxic effects are mainly in the central nervous system,
repiratory system, and endocrine system. |
| Diagnosis
Clinical
signs. CNS depression is the most
commonly observed sign of poisoning in dogs. Hyperexcitability,
vomiting, salivation, muscle tremors, and ataxia may also be seen in
intoxicated animals. Intoxication usually lasts a few hours.
In severe cases, coma and death are rarely seen.
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| Treatment. Mild
intoxication requires only close observation and sedation. Induced
emesis, oral activated charcoal, and bowel evacuation may be helpful in
reducing clinical signs in severe cases. Body temperature should
be closely monitored. |
| C. sativa is
one of the oldest cultivated plants. It was first
grown in China 6,000 years ago and has historically been
used to treat various medical symptoms including
insomnia, migraine headaches, and asthma. Today,
marijuana is used medicinally to treat glaucoma and to
relieve some of the side-effects of cancer
therapy. In the United States, medicinal use of
marijuana is controversial and use of marijuana without
a prescription is illegal. |
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