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Medicinal plants

Well before the advent of writing, humans used herbs for alimentary and medicinal purposes.

Medicinal plants

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Last update: 24/03/2020

By: Lúcia Gaspar - Librarian of the Fundação Joaquim Nabuco

The use of plants as medicine is probably as old as humankind itself. The concern with the cure of disease has always been a part of the history of humanity.

Well before the advent of writing, humans used herbs for alimentary and medicinal purposes. Looking for the most adequate vegetable species for their diet or to cure their ills, our ancestors discovered those that served best as food, as medication, those that were poisonous and those that caused hallucinogenic effects.

A medical work dating back to 3700 BCE, written by the Chinese Emporer Shen Wung, is one of the oldest known documents about the medicinal properties of plants. The Egyptians, 1500 BCE, were already using aromatic herbs in medicine, culinary and especially in their embalming techniques. The Sumerians from Mesopotamia possessed valuable prescriptions that were only known by the wise and wizards. In India, around the year 1000 BCE, the use of herbs was widespread.

During the Middle Ages, the cultivation of herbs used for food, drink and medicine was taken care of by monks, who planted them around the monasteries and churches.

In Europe, principally in England, alternative medicine has gradually become more favourable and in the United States there are a large number of natural pharmacies.

In Brazil, the knowledge of medicinal plant properties is one of the greatest riches of indigenous culture, a traditional wisdom that is passed down from generation to generation. Indians have a profound knowledge of medicinal flora with a large variety of medicines used in different ways. Their curative and preventative practices are related to the way they perceive sicknesses and their causes, practiced by the healers in rituals full of magical and mystical elements.

There is an enormous quantity of species in the world and the Amazon is home to 50% of the planet’s biodiversity. According to institutional data and studies on the region, approximately five thousand of the 25 thousand Amazon species have been catalogued and had their therapeutic properties studied.

Medicinal plants can be bought in public markets and herbal stores, be gathered in fields or cultivated in gardens, on farms or even in containers.

Over 25% of all medicines are of vegetable origin. Medicinal plants have always been a topic for study, looking for new ways to obtain their active properties, which are responsible for their pharmacological or therapeutic action.

From a scientific point of view, however, it is still an understudied and under-divulged field in the country, despite the richness of Brazilian flora, with studies in the area being restricted to anthropology and folklore through popular medicine.

Despite many plants being useful to humans, there are those that produce toxic or poisonous substances. The characteristics of each plant must be known well so that it can be used as a medicine.

It is common to hear it said that for medicinal plants, if it doesn’t do you good, it won’t do you harm, however this is not the case. Their misuse can bring undesirable effects. A good understanding of the disease or the symptoms presented is required to make the correct selection of the plant to be used, as well as its appropriate preparation. The way it is used, the frequency and the quantity are very important aspects of its application. The dosage should take into account the age and the metabolism of each person.
Medicinal plants can be prepared in various ways:

•         poultices (preparing a type of balm for external or topical use);
•         decoction (boiling to dissolve the substances through prolonged action of water or heat);
•         inhalation (combining water vapour with the volatile substances of aromatic plants);
•         infusion (traditional method for preparing teas);
•         maceration (a vegetable substance comes into contact with alcohol, oil, water or another liquid to dissolve the active ingredient);
•         juices (strained through fabric, crushed in a blender or with a pestle and mortar, with sugar possibly added);
•         medicinal wines (concoctions to dissolve vegetable substances in pure wine);
•         potions (solutions to which syrups, dyes, extracts or other ingredients are added);
•         roasting (using fire to remove water and change some of the plant’s properties);
•         ointments and creams (prepared through mixing the juice, dye or  tea of the medicinal plant with petroleum jelly or lanolin).
•         syrup (concoctions from the dissolved substances of the plant with sugar and heated water,).

Medicinal plants are used for very different effects, including: anti-mucus (inhibiting the formation of mucus); anti-spasmodic (avoids or relieves painful muscular contractions); anti-flatulence (eliminates intestinal gases); anti-rheumatic (combats rheumatism); anti-cough (inhibits coughing); diuretic (assists in the elimination of liquid from the kidneys); emetic (provokes vomiting); expectorant (eliminates  mucous from the respiratory system); haemostatic (stops haemorrhages); laxative (loosens the intestine); anti-motility (hardens the intestines).

Below are some of the medicinal plants with their popular English or local names and therapeutic values, in alphabetical order:

aloe – the gel from its leaves is used as an anti-dandruff shampoo, to combat hair loss and to clean wounds, ulcers, eczema and haemorrhoids;
andiroba – the oil from the seeds rubbed together is used for bursitis and neuralgia, working also as an insect repellent;
anise – tranquiliser, anti-spasmodic, aphrodisiac and diuretic;
arnica – works for bumps, bruises;
avocado – the skin is anti-worm and anti-hemorrhagic; the grated stone is a hair tonic and the tea of its leaves are for renal problems;
basil – the tea with milk is a cough suppressant;
boldo – digestive, anti-toxin, combats constipation and is used for intermittent fevers;
Brazilian cherry (pitanga) – the tea from its leaves helps to lower temperatures;
Brazilwood – the infusion of its leaves is recommended for combating diabetes;
bur – tea from the leaves serve to combat diarrhoea and renal problems;
cabacinha – used in an infusion to combat sinusitis. The tea is abortive.
camomile – anti-spasmodic, anti-neuralgic, digestive, combats hives and throat inflammations;
eucalyptus – the tea fights fever and inhalation serves for sinusitis and bronchitis;
fava beans – an infusion with the leaves is used for baths and plasters used against impetigo;
guava – the tea of the young sprouts serves to combat diarrhoea;
ipecacunha – the tea from its roots combats chest pains, ulcers and syphilis. Its syrup is used against colds;
jabuticaba (Brazilian grape) – gargling with the skin of the cooked fruit serves for problems with the throat;
jurubeba (nightshade) – detoxifier and combats liver problems;
laurel (bay) – the tea from the leaves is used against rheumatism and neuralgia;
lemon balm – the tea is soothing and is good for the stomach and combats diarrhoea;
lemongrass – tranquiliser, used also against diarrhoea and hypertension;
mastruço – expectorant, anti-inflammatory and its tea works for  colic;
mint – anti-spasmodic, acts against vomiting, combats migraines;
mulungu – the tea is recommended for bronchitis, asthma, fever and hepatic problems, bathing with an infusion of the bark is soothing and combats insomnia;
passionfruit – both the leaves and fruit are calmatives;
pomegranate – the infusion with its fruit’s peel is an anti-toxin and digestive, also with an anti-spasmodic action;
pumpkin – anti-worm, especially for tapeworms;
purple garlic – toothache, cramps, flatulence, asthma and constipation;
stonebreaker – the tea is anti-toxic and diuretic, recommended for dissolving gallstones.
soursop – the tea from the leaves is used against diabetes;
sweet basil – anti-flu, diuretic and reducing blood pressure. The seed are used against gonorrhoea;
unha-de-vaca – recommended to combat diabetes.
watercress – respiratory system illnesses, anti-anaemic and digestive;
watermelon – diuretic.

Recife, 30 June 2008.
(Updated on 8 September 2009).
Translated by Peter Leamy, March 2011.

sources consulted

BREVE história das ervas. Disponível em: <>. Acesso em: 26 jun. 2008.
ERVAS medicinais. Disponível em: <>. Acesso em: 26 jun. 2008.
PLANTAS medicinais. Disponível em: <>. Acesso em: 26 jun. 2008.
PLANTAS e ervas medicinais da Amazônia: um mercado em expansão. Disponível em: <>. Acesso em: 26 jun. 2008.
SOSSAE, Flávia Cristina. Plantas medicinais. Disponível em: <>. Acesso em: 25 jun. 2008.

how to quote this text

Source: GASPAR, Lúcia. Medicinal plants. Pesquisa Escolar On-Line, Joaquim Nabuco Foudation, Recife. Available at: <>. Accessed: day month year. Exemple: 6 Aug. 2009.