Can yarrow help to heal wounds?
BACKGROUND
Yarrow has for many centuries been used as a way to stop bleeding. Its scientific name, Achillea millefolium, comes from Greek mythology regarding Achilles, who is said to have always carried it into battle to stop bleeding from his soldiers’ wounds. The Romans called it Herba militaris, or the military herb, while its name in Irish was “lus na fola”, or the blood plant. It was used in many magical spells, and even believed to have power over the “evil eye”. Such practices led to it being used to treat many different ailments.
The leaves are edible and were used as a vegetable at various times during history. Medicinally, the flowering tops are usually extracted to make a remedy that is said to dry up many types of discharges. Externally, this can be applied to wounds to stop bleeding, but ironically was also said to cause nosebleeds in order to relieve headaches.
Currently, yarrow is sometimes added to cosmetics as a general healing agent, and is available in teas and as capsules. Taken internally, it is believed to reduce phlegm from colds and flu, and to relieve digestive problems. It is frequently found in combination products containing many herbs.
EVIDENCE FROM STUDIES
Because of the general interest in herbal remedies, yarrow has been the subject of renewed attention. This has led to several scientific studies of the contents of yarrow, though hardly any research has progressed to clinical studies. An essential oil has been extracted from the flowers which is a potent antioxidant. Some laboratory tests have shown the oil to be more potent than vitamin C as an antioxidant.
Because of its use with wounds, yarrow has been examined for anti-microbial properties. Several dozen species occur in the genus Achillea, of which Achillea millefolium had the weakest anti-microbial activity. More hopeful results were found in tests for anti-inflammatory activity. A number of animal studies found that yarrow extracts were potent in preventing inflammation.
Other studies found that wounds on animals healed more quickly when treated with a cream containing 5 per cent yarrow extract. However, in
spite of this being the most widely discussed application of yarrow, no controlled studies with humans were found.
The only report involving humans was a series of case studies in which yarrow was used by women with heavy menstrual bleeding. Many women reported beneficial effects, but this study did not use any control group. In these cases, yarrow was added to warm water to make a sitz bath.
PROBLEMATIC ASPECTS
Yarrow causes allergic skin reactions in many people. One study found that nearly half the people tested had such a reaction. Yarrow is a member of the daisy family, so anyone allergic to these plants should be careful. This is particularly important with the use of yarrow in cosmetics. Regulatory agencies have urged caution in using yarrow during pregnancy, primarily because so little is known about its effects on the unborn.
RECOMMENDATIONS
Yarrow is a herbal remedy with a long tradition of use. Many cultures in different eras have used yarrow, and often for the same purpose of healing wounds. However, such uses have rarely been investigated in scientific studies, and almost no studies in humans exist. Because of its reputation for causing allergic reactions, creams should be applied cautiously at first. Anyone with any type of bleeding condition should likewise be cautious before taking yarrow internally.
Dónal O’Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University
