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Camellia sinensis, tea


The 'cup that cheers but not inebriates' turns out to contain a highly addictive substance, caffeine, withdrawal of which results in a variety of unpleasant effects.



Meaning of the Name

Named for Father Georg Josef Kamel (1661-1706) who, in 1704, published an account of the plants of the Phillipines where he was a Jesuit missionary. He used the nom de plume ‘Camellus’.

Common Names and Synonyms


How Poisonous, How Harmful?

Contains caffeine and tannin. Caffeine is addictive; five cups a day are said to be sufficient to produce addiction. Withdrawal or reduced usage after excessive consumption leads to dizziness, headaches, constipation, indigestion, palpitations and insomnia.

Camellia sinensis, tea

Camellia sinensis, tea


Doctors in Italy have reported the case of a 13 year-old boy who chewed two packs of stimulant gum in four hours and required hospitalisation as a result of caffeine overdose. His parents were alerted when he returned from school agitated and aggressive.

After, initially, denying that anything was wrong, he said that he had abdominal discomfort, prickling in his legs and increased (and painful) passing of urine. When tested, his breathing, heart rate and blood pressure were all found to be elevated.

Doctors at the hospital identified caffeine as the cause of his symptoms and he recovered overnight and was discharged in the morning.

A man spent two weeks working away during which he drank fourteen cups of tea a day. On his return home, he resumed his normal intake and suffered ‘the worst hangover’ he’d ever known with headaches, stomach upsets, heart palpitations, sleepless nights and general debility.

A clinical pharmacologist, said she had been involved in a drug trial in which one of the patients produced a completely different reaction to all the others. It turned out he had been consuming huge amounts of coffee and the caffeine had affected the action of the drug on trial.

In October 2010, a coroner recorded a verdict of accidental death in the case of Michael Bedford, 23, who, in April 2010*, swallowed two teaspoons of pure caffeine at a party in Nottinghamshire, UK. The caffeine had been purchased online and the container warned that no more that the equivalent of one-sixteenth of a teaspoon should be taken at a time.

*Entirely as an aside, it is interesting to note that, at the time, there were no reports in the media of this death. Compare that to the many, hysterical reports of deaths assumed to be due to mephedrone which subsequently were found to have other causes.

Folklore and Facts

The effects of caffeine addiction are, often, underestimated because it challenges the general view of what being an 'addict' means. But the physical affects of caffeine withdrawal are well documented and can be similar to withdrawal from tobacco or heroin.

In a paper given at the 2002 International Symposium on the History of Anaesthesia, M van Wijhe, notes the effects of caffeine withdrawal and suggests that this might be the cause of some post operative discomfort. He thinks giving caffeine post operation might alleviate these effects.

The introduction of substances like tea, coffee, chocolate and tobacco into Europe was, often, influenced by economic, political and social factors. In some parts, their adoption was opposed by the authorities because it was felt that men gathering together to drink or smoke could be a cover for political dissidents to meet. In others, the interests of local alcohol producers were defended by official opposition to the new beverages. (For some time smoking was referred to as having a drink of tobacco.)

On the other side, consumption was, sometimes, encouraged by claims of medical efficacy though such claims may have been based on the desire of the importers to boost sales.

Cornelis Bontekoe was a member of the 17th century Dutch empirical medical school which sought to use concepts of healthy and unhealthy to overthrow the belief in the ‘humours’. He was, later, as private physician to Frederick William of Brandenburg, one of the key people in bringing coffee to German society. Prior to that he had, whilst rumoured to be in the pay of the Dutch East Indies Company, said that drinking 8 to 10 cups of tea a day was the minimum required to obtain its health benefits but he saw no reason not to drink up to 100 cups a day.

A study , in November 2008, suggested that ingestion of caffeine during pregnancy may result in reduced birth weight. The study enrolled women early in pregnancy and asked them to monitor their caffeine intake throughout their pregnancy. Based on the results, it has been suggested that pregnant women should keep their caffeine intake below 100mg per day, which is about two cups of instant coffee.

In the context of this webpage, however, the most interesting finding was that 62% of total caffeine came from tea.

The pub quiz question 'Which has more caffeine; tea or coffee?' is interesting because there is no correct answer. Though a kilo of dry tea contains more caffeine than the same weight of coffee, a cup of coffee contains more caffeine than the same size cup of tea.

There have been reports from the USA of deaths arising from excessive consumption of 'energy drinks'. These have been said to be a result of caffeine overdose but the total caffeine content of the drinks consumed seems to be well below the lethal dose.


The POISON GARDEN website is not connected with Alnwick Garden Enterprises Ltd and/or The Alnwick Garden Trust.


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Introduction to the A to Z section
Abrus precatorius, rosary pea
Aconitum lycoctonum, wolfsbane
Aconitum napellus, monkshood
Actaea racemosa, black cohosh
Actaea spicata, baneberry
Aesculus hippocastanum, horse chestnut
Amanita muscaria, fly agaric
Aquilegia atrata, columbine
Aristolochia clematitis, birthwort
Artemisia absinthium, wormwood
Arum italicum, Italian cuckoopint
Arum maculatum, cuckoopint
Aspergillus fumigatus
Atropa belladonna, deadly nightshade
Brugmansia suaveolens, angel's trumpet
Bryonia dioica, bryony
Buxus sempervirens, common box
Camellia sinensis, tea
Cannabis sativa, marijuana
Catha edulis, khat
Chelidonium majus, greater celandine
Cimicifuga racemosa, black cohosh
Claviceps purpurea, ergot
Clematis vitalba, old man's beard
Colchicum autumnale, naked ladies
Conium maculatum, poison hemlock
Convallaria majalis, lily of the valley
Cynoglossum officinale, hound’s tongue
Daphne mezereon, spurge olive
Datura stramonium, thorn apple, jimsonweed
Datura suaveolens, angel's trumpet
Delphinium, larkspur
Digitalis spp., foxglove
Dracunculus vulgaris, dragon arum
Echium vulgare, viper’s bugloss
Eranthis hyemalis, winter aconite
Erythroxylum coca, cocaine
Euonymus europaeus, spindle tree
Euphorbia x martinii, red spurge
Euphorbia pulcherrima, poinsettia
Fritillaria spp., fritillary
Galanthus nivalis, snowdrop
Hedera helix, common ivy
Helleborus spp., hellebore
Heracleum mantegazzianum, giant hogweed
Hyacinthoides non-scripta, bluebell
Hyoscyamus niger, black henbane
Ilex aquifolium, holly
Jacobaea vulgaris, ragwort
Juniperus communis, common juniper
Laburnum anagyroides, laburnum
Lactuca serriola, prickly lettuce
Leucojum aestivum, snowflake
Lithospermum officinale, gromwell
Lolium temulentum, darnel
Malus 'John Downie', crab apple
Mandragora officinarum, mandrake
Mercurialis perennis, dog’s mercury
Narcissus, daffodil
Nepeta faassenii, catmint
Nerium oleander, oleander
Nicotiana sylvestris, tobacco
Oenanthe crocata, hemlock water dropwort
Papaver somniferum, opium poppy
Pastinaca sativa, parsnip
Polygonatum odoratum, angular Solomon's seal
Prunus laurocerasus, cherry laurel
Pulsatilla vulgaris, pasque flower
Ranunculus acris, meadow buttercup
Rheum x hybridum, rhubarb
Rhododendron spp.
Rhus radicans, poison ivy
Ricinus communis, castor oil plant
Rosmarinus officinalis, rosemary
Rumex obtusifolius, broad-leaved dock
Ruta graveolens, rue
Salix alba, white willow
Salvia divinorum, sage
Scutellaria laterifolia, Virginian skullcap
Senecio jacobaea, ragwort
Solanum dulcamara, woody nightshade
Solanum melongena, aubergine
Strychnos nux-vomica, poison nut
Symphoricarpos albus, snowberry
Symphytum spp., comfrey
Taxus baccata, yew
Toxicodendron radicans, poison ivy
Thevetia peruviana, yellow oleander
Urtica dioica, stinging nettle
Veratrum album, white hellebore
Verbascum olympicum, Greek mullein
Vinca major, greater periwinkle
Viscum album, mistletoe
Vitex agnus-castus, chaste tree