foxglove plant has been part of folklore for centuries and traditional medicine for just as long, where it has been used to treat heart conditions and dropsy. The first systematic and scientific study of extracts of the plant was not made until the late eighteenth century by William Withering (1741–1799), a doctor from Shropshire. Withering noticed that one of his patients suffering from dropsy recovered after using a herbal remedy given to him by ‘the old woman of Shropshire’.
Dropsy, now known as oedema, is swelling caused by an accumulation of fluid in the body. Oedema has several causes, but is often due to either weak action of the heart or cirrhosis of the liver. Fluid filters out of the blood and is reabsorbed at the capillaries. The balance between filtering and reabsorption depends on the resistance of the blood and blood pressure. Under normal conditions the rate of filtration is higher than that of absorption, and the excess fluid is removed from the tissues by the lymphatic system. Fluid is returned to the blood from the lymphatic system at the superior vena cava, one of the large veins that take deoxygenated blood back to the heart. Fluid is permanently removed from the blood by filtration through the kidneys. All the blood in a human is filtered by the kidneys roughly every half-hour, and excess water is excreted via the bladder.
A person with a weak pulse due to heart failure is unable to expel blood from the ventricles of the heart efficiently. This results in an increase in blood pressure, and therefore an increase in the filtering of fluid into the tissues. The kidneys respond by retaining more fluid, so there is very little urine output. This leads to swelling in the legs and arms, and difficulty breathing as fluid builds up around the lungs.
After observing the successful treatment of his patient, William Withering sought out ‘the old woman of Shropshire’ and asked her what went into her herbal treatment.She wouldn’t disclose the recipe, but Withering persuaded her to give him some of the preparations. By examining them under a microscope he identified fragments of foxglove.
Withering began what were effectively clinical trials of digitalis, which ultimately involved 163 patients. He gave his dropsy patients small amounts of various foxglove preparations, and observed their effects. He found dried and powdered foxglove leaves given by mouth to be the most effective treatment. Carefully increasing the dose, he monitored his patients’ progress, recording results, both successful and unsuccessful, in his notebook.
The principles behind clinical trials have ancient origins stretching back to the time of the Old Testament, but they were not routinely used to assess the positive and negative effects of diet or drugs until the twentieth century. Withering’s detailed study stands out because of his systematic approach to the use of foxglove preparations, and his careful notation of the adverse as well as the beneficial effects of these preparations. In his investigation, Withering noted that foxglove was extremely effective for some of his patients but not others. We now know that herbal preparations would be effective for dropsy caused by heart conditions, but they offered no help to those who were suffering from dropsy caused by cirrhosis of the liver. Withering also noted that at higher doses toxic effects developed, and he described the symptoms in detail.
Withering wrote up his observations in a treatise entitled An Account of the Foxglove and some of its Medical Uses (1785), still considered a classic of its kind. The book was widely read, and treatments were given to an increasing number of patients. However, some doctors grew impatient with the cautious and slow approach to foxglove treatments. Withering recommended that very small doses should be given initially and slowly increased until the desired effect was observed, in order to prevent toxic side effects. The extreme potency of
Dropsy, now known as oedema, is swelling caused by an accumulation of fluid in the body. Oedema has several causes, but is often due to either weak action of the heart or cirrhosis of the liver. Fluid filters out of the blood and is reabsorbed at the capillaries. The balance between filtering and reabsorption depends on the resistance of the blood and blood pressure. Under normal conditions the rate of filtration is higher than that of absorption, and the excess fluid is removed from the tissues by the lymphatic system. Fluid is returned to the blood from the lymphatic system at the superior vena cava, one of the large veins that take deoxygenated blood back to the heart. Fluid is permanently removed from the blood by filtration through the kidneys. All the blood in a human is filtered by the kidneys roughly every half-hour, and excess water is excreted via the bladder.
A person with a weak pulse due to heart failure is unable to expel blood from the ventricles of the heart efficiently. This results in an increase in blood pressure, and therefore an increase in the filtering of fluid into the tissues. The kidneys respond by retaining more fluid, so there is very little urine output. This leads to swelling in the legs and arms, and difficulty breathing as fluid builds up around the lungs.
After observing the successful treatment of his patient, William Withering sought out ‘the old woman of Shropshire’ and asked her what went into her herbal treatment.She wouldn’t disclose the recipe, but Withering persuaded her to give him some of the preparations. By examining them under a microscope he identified fragments of foxglove.
Withering began what were effectively clinical trials of digitalis, which ultimately involved 163 patients. He gave his dropsy patients small amounts of various foxglove preparations, and observed their effects. He found dried and powdered foxglove leaves given by mouth to be the most effective treatment. Carefully increasing the dose, he monitored his patients’ progress, recording results, both successful and unsuccessful, in his notebook.
The principles behind clinical trials have ancient origins stretching back to the time of the Old Testament, but they were not routinely used to assess the positive and negative effects of diet or drugs until the twentieth century. Withering’s detailed study stands out because of his systematic approach to the use of foxglove preparations, and his careful notation of the adverse as well as the beneficial effects of these preparations. In his investigation, Withering noted that foxglove was extremely effective for some of his patients but not others. We now know that herbal preparations would be effective for dropsy caused by heart conditions, but they offered no help to those who were suffering from dropsy caused by cirrhosis of the liver. Withering also noted that at higher doses toxic effects developed, and he described the symptoms in detail.
Withering wrote up his observations in a treatise entitled An Account of the Foxglove and some of its Medical Uses (1785), still considered a classic of its kind. The book was widely read, and treatments were given to an increasing number of patients. However, some doctors grew impatient with the cautious and slow approach to foxglove treatments. Withering recommended that very small doses should be given initially and slowly increased until the desired effect was observed, in order to prevent toxic side effects. The extreme potency of
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