How Do Cardiac Remedies Work?
The strong and effective cardio-active remedies owe their power to the presence of the cardiac glycoside group of plant constituents. These have the effect of increasing the efficiency of the muscles of the heart without increasing their need for oxygen. This enables the heart to pump enough blood around the body and ensure there is not a build-up of fluid in the lungs or extremities. That sounds wonderful, as indeed it is, but there is always the possibility of accruing too much of the glycosides in the body as the removal rates tend to be low. This is the main drawback of Foxglove and why it is potentially poisonous, unless used with skill and knowledge. The clinically trained medical herbalist uses Lily of the Valley in preference to Foxglove as there is less chance of such problems developing.

Another group of remedies, called Cardio-Tonics, have an observably beneficial action on the heart and blood vessels but how they work is either completely obscure or an area of great pharmacological debate. Flavones appear to be major contributors to the beneficial role of these tonic remedies. These remedies are herbs such as Hawthorn, Linden, Garlic and Motherwort. The search for plants with cardiovascular activity is being undertaken by pharmacologists around the world. This is not simply for herbs and new constituent compounds with the potency of the cardiac glycosides, but also substances for adjuvant heart therapy, for geriatric heart conditions or milder cardiac insufficiency. In their search a number of approaches are used in selecting herbs for testing. Acknowledgment of the value of herbal traditions plays a large part. This hassled to the identification of various cardio-tonic substances including phenylalkylamines found in the Night Blooming Cereus, alkaloids such as those in Prickly Ash and Scots Broom, and flavonoids from Hawthorn and Bilberry.

Cardiac Tonics for Different Parts of the Body
By the very nature of such a specific action, it is not usually directly relevant to all the body systems. Many of the cardiac tonics will have other actions on the body, however, and it is this range that we will explore here.

Circulatory system: The primarily cardio-active remedies include Lily of the Valley, Foxglove, Broom, Squill, Figwort and Bugleweed, while the tonic remedies include Hawthorn, Linden, Garlic and Motherwort. Remedies that specifically benefit the vessels include Hawthorn, Linden, Horsechestnut, Garlic, Ginkgo and Yarrow.

Respiratory system: Any problem with the action of the heart might have an effect on lung congestion via a 'backlog' of blood waiting to be pumped. So the cardiac tonics may benefit the lungs by helping the heart rather than directly helping the chest itself. Garlic is renowned for its anti-microbial and generally beneficial action on the lungs, and Angelica is another gentle cardiac tonic that will help lung problems.