Tanja Grkovic inspects a 384 well plate containing natural product chemical fractions before it is shipped out for screening.

FREDERICK, Md. -- Tree bark, microbes, and mold are not simply the stuff you rake in the back yard and track in on the bottom of your shoes. They just might be a treatment for a rare disease. 

Products found in nature gave rise to some of our most familiar and relied-upon therapies including some antibiotics and decongestants and aspirin. There may be another treatment contained in a sea sponge or a leaf, but sifting through to isolate that compound is a complex undertaking. Scientists find natural products notoriously difficult to work with.