Use the flowering tops, leaves, and upper stems to make a tincture or a salve. Blessed thistle was commonly used during the Middle Ages to treat the bubonic plague and as a tonic for monks. Blessed thistle is prepared as a tea and used for loss of appetite and indigestion; and to treat colds, cough, fever, bacterial infections, and diarrhea. It is also used as a diuretic for increasing urine output, and for promoting the flow of breast milk in new mothers. Soak gauze in blessed thistle and apply it to the skin for treating boils, wounds, and ulcers. In manufacturing, blessed thistle is used as a flavoring in alcoholic beverages. Don’t confuse blessed thistle with milk thistle (Silybum marianum). Blessed thistle contains tannins which help diarrhea, coughs, and inflammation.