In most medical and toxicological specialties the administered dose absorbed is deﬁned precisely. This has not always been so in dermatoxicoiogy and dermatopharmacology. The absorbed dose is usually deﬁned as percent applied dose absorbed, ﬂux rate, and/or permeability constant. This may sufﬁce for the person creating the data, but it is incomplete for the person judging the worthiness of the data. Chemical absorbed through skin is usually a low percentage of the applied dose. If 5% is absorbed, it is more than curiosity to question where the other 95% resides. Most critical is whether the remaining dose was in place during the course of the study and whether there is dose accountability. A second critical question is where the clinical or toxicological response lies in relationship to the topically applied dose, the standard safety and efﬁcacy issue that a dose-response will provide. The third question is whether absorption is linear to administered dose, i.e. the dose-response.