There are several ways to enhance the effectiveness of the tea.
You can increase the ratio of tea/water from 3 Tbls. to 4-6 Tbls. per quart. You can find your comfort level. Extremely strong mixtures do not necessariy increase the effectiveness of the tea.
You can add any sweetener to the tea such as honey, Stevia or fruit juice. Mixing with frozen concentrated fruit juice really improves the taste. Stevia (a few drops) and lime juice (1-2 teaspoons) makes a delightful drink.
I use a liquid Pau D'Arco Extract for various purposes. (See "The List" webpage). You can purchase the Extract and Liquid Stevia at most nutrition stores and on the Internet.
Pau d'Arco Baths can be soothing and has been suggested to hold medicinal qualities. Prepare about 1 1/2 quarts, "double strength" tea and add to bath water (heated to slightly more than body temperature). Bathe for 30 minutes (no soap) and then wrap youself in a warm fleecy bathrobe or towel and rest for at least 20 minutes.
"Double stength" tea has also be used for external applications.