This herb, commonly known as yarrow, is one of the first to be studied, thanks to the alphabetical ordering if its scientific name. It is classified as a warming herb, mainly due to its effects on circulation, i.e. increaasing it to the peripheries. This action also makes yarrow one of the superlative diaphoretic remedies - that it, it can help break a fever. Diaphoretics were once much more important in the practice of medicine, in a time when having a fever was a more serious issue. In fact, fevers were once seen as a disease state in themselves, rather than as the body's normal immunological response as it is considered nowadays. Western Herbal Medicine still uses some of the approaches that were used in conventional medicine, such as employing diaphoretics, back when the distinction between the two was blurry, if not non-existent.
Yarrow's effects on the circulation means it will be used in situations where promoting circulation in general is key to restoring optimum function and eliminating symptoms - which is a lot of situations! This could mean it would be useful for:
colds, fevers, flu-like states
muscular/skeletal disorders including fibromyalgia and arthritis
lowering elevated diastolic blood pressure
Different sources (and sometimes the same source) will list yarrow as both a circulatory 'stimulant' and haemostatic (i.e., stops bleeding). While on the face of it this may seem contradictory, an experienced herbalist once told me it was because the deeper action of this herb is more like "circulation normalizer - it makes sure blood is where it needs to be". If we think of herbs only in terms of standard pharmacy, this can be problematic, as most drugs have one specific action that usually occurs in one of two 'directions', e.g. cholinergic or anticholinergic, hypotensive or hypertensive etc. However, herbs are much more complex, and frankly unpredictable. Many have the ability to give what the body needs in order to maintain or restore proper function, which may be a particular action in one person, yet the seemingly opposite in another.
Yarrow is also known to have some bitter principles in, as such it has a stimulating effect on digestion. Another reason it might be found in a lot of prescriptions.
Click here to watch my video clip on tasting yarrow tincture!