Dibenzothiophene (DBT) is the organosulfur compound consisting of two benzene rings fused to a central thiophene ring. It is a colourless solid that is chemically somewhat similar to anthracene. This tricyclicheterocycle, and especially its alkyl substituted derivatives, occur widely in heavier fractions of petroleum. A drug that softens, separates, and causes desquamation of the cornified epithelium or horny layer of skin. DBT was used to treat acne, seborrhea and related dermatoses.