Tea Tree Essential Oil . I provided a link to give you an idea of the many uses.
http://www.buzzle.com/articles/tea-tree-oil-research-benefits-and-uses.html

Size/Texture:

Each bar weighs 4 ounces each . The all black color is from the activated charcoal blended with moisturizing shea butter especially for the cooler weather

INGREDIENTS:

vegan soap base, activated food grade charcoal and tea tree essential oil.

ALLERGEN ALERT:

Shea butter comes from a nut