I assume that you're referring to Dianabol, it's an anabolic steroid.
here is some info:
Methandrostenolone (Dianabol)
Description
by Bill Roberts
Contrary to what many would expect, this compound is actually only a weak agonist of the androgen receptor (AR), with poor binding. It follows, then, that its value must mostly come from non-AR-mediated effects. It is therefore a Class II steroid. Since it is not very effective in activating ARs, it should be stacked with a Class I steroid that is effective in this regard, such as Primobolan, Deca Durabolin, or trenbolone acetate. There is no point in stacking it with Anadrol, which has similar activity -- one ought to simply use the more appropriate drug. With testosterone or Deca, Dianabol is to be preferred; with Primobolan or trenbolone acetate, Anadrol is to be preferred (though Dianabol is still a good choice) because Anadrol does not aromatize. For an oral-only cycle -- something I don't recommend -- Anadrol is the better choice in my opinion for that also, at 150 mg/day (preferably divided to 3 or 6 doses.)