In Herbal Medicine, with its ancient traditions, the term diuretic has come to imply a herb that has some sort of beneficial action on the urinary system. Thus not only are diuretics as such included, but can also urinary demulcents and anti-inflammatory remedies. This can, regrettably, lead to confusion when selecting remedies for a particular individual. Hopefully what follows will clarify this situation to some degree.

How do Diuretics Work
If we limit ourselves to the strict sense of the word, there appear to be two broad groups, those that increase kidney blood flow and those that reduce the water reabsorption in the nephrons of the kidney.

The first group includes not only diuretics such as Broom but all the herbs that are cardio-active and circulatory stimulants. These increase the blood flow in the kidney by effects on the heart or elsewhere in the body. Because there is more blood passing through the kidney, more urine is produced. Caffeine-containing herbs such as Kola, Guarana, Tea and Coffee also have this effect

* The second group work in a number of different ways, but they cause diuresis be cause some of their constituents are secreted via the kidney. This may change the osmotic balance causing more water to be lost. This appears to be the case with Dandelion Leaf, Couch grass and Corn silk. Others work by irritating there absorption mechanism in some way, either through volatile oils, saponins or alkaloids.

Varieties of "Diuretic"
In addition to the herbs that have a markedly diuretic impact, there are others called "diuretics" that have other than a primarily diuretic effect upon the kidneys. The phytotherapist has the option to reduce inflammation through demulcents and anti-inflammatories. Infection can be treated directly through "diuretics" that are anti-microbial. Similarly, if these problems are associated with stone formation there are plants known as anti-lithics, discussed in the section on calculus.

Anti-Lithic: Gravel Root, Hydrangea, Stone Root

Anti-microbial: Bearberry, Buchu, Couch grass, Juniper, Yarrow

Astringent: Agrimony, Bearberry, Broom, Horsetail, Kola, Yarrow

Demulcent: Bearberry, Corn Silk, Couch grass, Stone Root

Diuretics for Different Parts of the Body
The core of the model used throughout this book is that each herb has a range of actions and that some have specific system and organ affinities. The fundamental importance of both the urinary system and diuretics, emphasize the possibilities if secondary actions and system affinity is taken into account. To clarify this consider the following:

Circulatory system: As already pointed out, the cardio-active remedies have a diuretic effect because they increase blood flow through the kidneys. Remedies for this system include Lily of the Valley, Broom, Dandelion and Yarrow. The first two are cardio-active and the others are tonic. All diuretics help remove water from the body and can be of benefit for the cardiovascular system. Care should be taken to ensure the right ones are used in the specific condition being treated. Broom should not be used in high blood pressure, for example.

Respiratory system: If pulmonary congestion is occurring due to heart problems, then most of the diuretics will be of value. Remedies that have an affinity for this system include Boneset, Cleavers, Elder, Yarrow and Eucalyptus.

Digestive system: Some of the laxative herbs act as diuretics as well. Here we can mention Agrimony, Blue Flag, Boldo, Borage, Celery Seed, Dandelion, Parsley, Pumpkin Seed.

Reproductive system: The antiseptic diuretics often work in the same way on the reproductive system. Of special relevance is Bearberry. Saw Palmetto is a mild diuretic.

Muscles and skeleton: Because of their cleansing action, many diuretics help in problems of muscles and bones. Boneset, Celery Seed, Yarrow and Gravel Root are but a few.

Nervous system: Borage and Bugleweed are the only real diuretics to impact the nervous system directly. However, if there is much tension, using a nervine to relax may allow more urine to be passed.

Skin: All the diuretics potentially help the skin by an inner cleansing process. Especially important are Cleavers, Couch grass and Dandelion. An important point is that some diuretics act as diaphoretics when drunk hot.