Chemically it is (5aR-(3aS*,5aα,8b,8aS*,9a,10aα))-9-(1,1-dimethylethyl)-10,10a-dihydro-8,9-dihydroxy-4H,5aH,9H-furo[2,3-b]furo[3',2':2,3]cyclopenta [1,2-c]furan-2,4,7(3H,8H)-trione.
Bilobalide is a main constituent of the terpenoids found in Ginkgo leaves. It also exists in minor amounts in the roots. It is a sesquiterpenoid, i.e. it has a 15-carbon skeleton. Its exact synthesis pathway from farnesyl pyrophosphate is still unknown.