Lovage is a plant. The root and underground stem (rhizome) are used to make medicine.
Lovage is used for kidney damage in people with (diabetic nephropathy), indigestion, kidney stones, cough, and many other conditions, but there is no good scientific evidence to support these uses.
In foods and beverages, lovage is used for flavoring.
In manufacturing, lovage is used as a fragrance in soaps and cosmetics.