Do you mean literal dirt or dope?
I agree with Pat, you should see your Dr. It very well could be a mineral deficiency.
I obsessively craved baby powder when I was pregnant. I never ate it, but thought of eating it constantly. Turned out it was just low iron. Not sure of correlation, but as soon as my iron level was normal, the baby powder obsession went away. And I was embarrassed to tell my Dr, but he told me cravings like this, and he specifically mentioned dirt, where more common than I could imagine.
This could be a known disorder called "Pica". You really need to consult your doctor as it could lead to numerous complications if you continue to eat dirt. You may have deficiencies that are making you crave dirt so please see your doctor.
How long have you had this addiction for dirt? Do you consume the dirt?