Traditionally, yellow dock (Rumex crispus) root has been thought to be a blood purifier and general detoxifier, especially for the liver. Rumex crispus, supports detoxification from a few angles. First off, yellow dock root stimulates bile production, which helps digestion, particularly of fats, also assisting in the relief of constipation.  It is useful in the treatment of chronic skin conditions such as psoriasis.  Yellow Dock combines well with dandelion, burdock & cleavers.  

"The Yellow Dock is applicable to all the purposes for which the other species are used. The root has laxative, alterative and mildly tonic action, and can be freely used as a tonic and laxative in rheumatism, bilious complaints and as an astringent in piles, bleedings of the lungs, etc. It is largely prescribed for diseases of the blood, from a spring eruption, to scurvy, scrofula and chronic skin diseases. It is also useful in jaundice and as a tonic to the stomach and the system generally. It has an action on the bowels very similar to that of Rhubarb, being perhaps a little less active, but operating without pain or uneasiness.

Rumicin is the active principle of the Yellow Dock, and from the root, containing Chrysarobin, a dried extract is prepared officially, of which from 1 to 4 grains may be given for a dose in a pill. This is useful for relieving a congested liver, as well as for scrofulous skin diseases.

A syrup can be made by boiling 1/2 lb. crushed root in a pint of syrup, which is taken in teaspoonful doses. The infusion administered in wineglassful doses - is made by pouring 1 pint of boiling water [approx 2 cups]on 1 OZ.[28g]  of the powdered root. A useful homoeopathic tincture is made from the plant before it flowers, which is of particular service to an irritable tickling cough of the upper air-tubes and the throat. It is likewise excellent for dispelling any obstinate itching of the skin. It acts like Sarsaparilla for curing scrofulous skin affections and glandular swellings.

To be applied externally for cutaneous affections, an ointment may be made by boiling the root in vinegar until the fibre is softened and then mixing the pulp with lard.

The seeds have been given with advantage in dysentery, for their astringent action.

The Yellow Dock has also been considered to have a positive effect in restraining the inroads made by xxxxxx in the human system, being used as an alterative and tonic to enfeebled condition caused by necrosis, xxxxxx, etc. It has been used in diphtheria." by Mrs Grieves, A Modern Herbal.