"Will it work?" is the question usually asked first and most frequently about any contraceptive method. This question is especially salient for women using teratogenic drugs and their clinicians, particularly dermatologists. As discussed in other articles in this issue of the ARCHIVES, dermatologists prescribe two of the most potent teratogenic drugs, isotretinoin (Accutane, Roche Laboratories, Nutley, NJ) and thalidomide. Because this question cannot be answered with certainty for any particular couple, most clinicians and counselors try to help patients understand factors influencing contraceptive efficacy.