Plants and their derivatives are currently the sources for thousands of drugs worldwide. But this does not mean that they are all safe or side-effect free. Isolated principles from plants such as morphine, reserpine, digitoxin, vincristine and vinblastine are toxic, due in part to their tremendous concentration.

Remember, the difference between a medicine and a poison is often the dose. A small amount of any of these compounds, properly employed can benefit health.

Too much of any of these compounds can lead to death. Plant medicines remain indispensable to modern pharmacology and clinical practice. Much of the current drug discovery and development process is plant-based, and new medicines derived from plants are inevitable.

Many drugs are made from plants. By way of illustration, here are a few plants and plant ingredients used in many conventional drugs.

SENNA - Senna alexandrina
A shrubby perennial native to Arabia, was introduced as a laxative to Europe by Arab physicians in the ninth century. Preparations of the plant and its cathartic pods are still widely used today in popular brands of drugstore laxatives. You can find senna in many drugstore laxative products.

MINT - Mentha

Species are the natural sources of menthol, an aromatic alcohol which is also known as peppermint camphor. Menthol is an active ingredient in topical preparations to relieve itching and as a mild local anesthetic to soothe soreness and ease muscular tension. Menthol is commonly used in lozenges for sore throats, and is added to inhalers to treat upper respiratory disorders and open congested sinuses.

Peppermint oil, which can still be found in drugstores, is a centuries-old remedy for quelling an upset stomach. Studies show that peppermint oil when taken internally can relieve irritable bowel syndrome.

WINTERGREEN - Gaultheria procumbens

Source of methylsalicylate, which is widely used in topical ointments and liniments to relieve muscular pain, and for lumbago, sciatica and rheumatic conditions.

OPIUM POPPY - Papaver somniferum

Yields a sap of narcotic opium, from which the potent pain killer morphine is made. Seeds and capsules discovered in the four-thousand-year-old archaeological remains of Swiss lake-dwellers suggest the use of the plant for its narcotic juice. In the eighth century Persian caravans bore both opium and its methods of euphoric use to India and China.

In 1546 a French naturalist named Belon drew European attention to widespread opium abuse among Turks. Opium dens proliferated in Europe throughout the 1800's, while the opium trade became an enormous industry. Simultaneously, opium and its products heroin and morphine established themselves among drug users and in the field of medicine.

Both uses continue to this day. In modern medicine, morphine and its analogues remain unsurpassed pain killers.

FOXGLOVE - Digitalis purpurea
The purple foxglove, is a popular garden plant cultivated as a source of digitoxin, a cardiac drug which increases the strength of heart beat while decreasing its rate. The plant was recommended for medicinal purposes in the seventeenth century, and has appeared in the French Pharmacopoeia since its first printing in 1818.

Digitoxin is used in the treatment of congestive heart failure and other cardiac disorders. Digitalis lanata, the woolly foxglove, is cultivated commercially as a source of digoxin, a cardiotonic used for the same purposes as digitoxin.

On a trip to Burma in 1930, an Indian named M. Manal discovered that elephants in captivity were often fed a particular type of root reputed to produce a calming effect. Intrigued, Manal brought samples of the plant back to India, where he conducted tests on its properties.

SNAKEROOT - Rauwolfia serpentina
Named after famous 16th century German physician and explorer Leonhart Rauwolf, demonstrated both tranquilizing and anti-hypertensive properties. These effects were due to the presence of the alkaloid reserpine.

In 1934 Serpina, the world's first-ever anti-hypertensive drug, was launched. Today reserpine is used both as an antihypertensive and as a sedative to relieve some types of psychiatric disorders.

CINCHONA - Cinchona pubescens
A fast-growing evergreen from Ecuador, as well as other species of cinchona, stand among the greatest life-saving medicines of all time. According to legend this plant was brought to light in the 1620's when Ecuadorean physician Juan del Vega used a Quichua native remedy known as "quina bark" on the Countess of Chinchon, wife of the Viceroy of Peru, who had contracted malaria, a potentially fatal disease caused by a protazoan in the stomach of the female Anopheles mosquito.

The Countess recovered, and "quina bark" became known as "Countess bark." Word of the cure spread, and cinchona was popularized by an apothecary's assistant named Robert Talbor in the late 1660's. Over the next 150 years a huge trade in cinchona bark developed. In the early 19th century, the Dutch established cinchona plantations in Java.

In 1820, quinine was isolated from cinchona, and a successful treatment for malaria was established. Today cinchona is cultivated in several tropical regions, and the approximately 10,000 tons of bark harvested annually yields 500 tons of quinine and related alkaloids quinidine, cinchonine, and cinchonidine.

CURARE - Chondodendron tomentosum
Members of Columbus' second trip to the Americas in 1493 were the first to experience curare, a poison on the tips of arrows which killed them promptly. Sir Walter Raleigh, on his 1595 voyage up the Orinoco River encountered similar poisoned arrows, and launched a legend which spawned the quest to find the source of the poison.

In 1799, explorer Baron von Humboldt witnessed a shaman preparing arrow poison from a vine. Von Humboldt brought some of the poison back to Europe, where it stupefied and asphyxiated animals subjected to it. Subsequent explorers attempted to find and identify the plant, but could not do so until 1938, when an American named Richard Gill found and successfully identified Chondodendron tomentosum, the source of curare. This led to the development of the valuable drug tubocurarine, which was used as an adjunct to general anesthesia, and in cases of spastic paralysis and plastic muscular rigidity.

YEW - Taxus brevifolia

In cancer treatment, the drug Paclitaxel (Taxol), a derivative of the Pacific Yew, is used in chemotherapy.

ROSE PERIWINKLE - Catharanthus roseus
The Madagascar periwinkle is the source of vinblastine and vincristine, alkaloids used respectively in the treatment of Hodgkin’s disease and pediatric leukemia.

ERGOT FUNGUS - Claviceps purpurea

Ergot is a toxic fungus which grows on rye kernels, and yields several valuable alkaloids including ergotamine, which is used to treat migraine. Interestingly enough, Ergot also yields lysergic acid, a derivative of which is C20H25N3O, or LSD (lysergic acid diethylamide).

First made by chemist Albert Hofmann in the laboratories of Sandoz Pharmaceuticals in Basel, Switzerland in 1938, LSD's effects were discovered accidentally by Hofmann in 1943. LSD subsequently became the cornerstone drug of the 1960's psychedelic revolution, and one of the most influential drugs in history.