White Willow Bark: Herb at the Edge of Enlightenment

The White Willow is an enchanting tree with a natural affinity for water, and its medicinal bark has a surprisingly long and winding history. Today, willow is best known as a source of salicylic acid and as one of the plants that ultimately led to aspirin. But its journey into British herbal medicine was rather less straightforward.

The medicinal virtues of willow were known in the ancient world. Hippocrates used willow leaves to ease the pains of childbirth, while Dioscorides later described willow preparations for ailments including colic, gout and earache. Yet this ancient knowledge seems to have made only a limited impression on the British herbal tradition.

By the sixteenth century, willow had begun to appear in English herbals. John Gerard included it in The Herball of 1597, drawing heavily on earlier ancient Greek and Roman sources, but there's little to suggest that he recognised willow bark as the useful remedy for headaches and fevers that it would later become.

In the following century, willow acquired another dimension, both magical and astrological when herbalist, Nicholas Culpeper, placed it under the dominion of the Moon! This an association seems particularly apt for a tree so intimately connected with water, tides and damp ground. He classified willow as cold and moist, and was among the first English herbalists to give detailed attention to its different parts. A decoction of the bark in wine, he wrote, could be used to staunch bleeding and ease stomach cramps.

It was not until the eighteenth century, however, that willow bark made its dramatic re-entry into the medical canon.

On a summer day in Oxfordshire, the Reverend Edward Stone noticed the extraordinarily bitter taste of willow bark and was reminded of another famous bitter bark: Peruvian bark, or cinchona, the precious source of quinine then used to treat intermittent fevers. Stone was intrigued by the resemblance. He reasoned that since willow flourished in the same damp places where agues were common, perhaps nature had placed their remedy close to their cause.

The Reverend Stone decided to test his idea.

He gathered nearly a pound of willow bark, dried it for several months over a baker's oven and reduced it to powder. Over the following years, he experimented with the preparation on people suffering from agues and intermittent fevers. By the time he wrote to the Royal Society in 1763, he had used it on around fifty people.

His letter, An Account of the Success of the Bark of the Willow in the Cure of Agues, marked a significant moment in the history of the remedy. Stone did not know about salicylic acid, nor could he have imagined the pharmaceutical revolution that would eventually follow. He simply observed that willow bark appeared to have medicinal power and carefully recorded his experiments.

His observations helped set in motion the scientific investigation of willow's active compounds, eventually leading to the isolation of salicylic acid and, much later, the development of aspirin.

And so the enchanting tree beside the river found itself at the meeting point of two traditions: the ancient herbal knowledge of its medicine, and the emerging experimental science of the eighteenth century, or the Age of Enlightenment.