The oral contraceptive (OC) Stediril acts by inhibiting ovulation, rendering the endometrium inhospitable to implantation, and rendering the cervical mucus impermeable to sperm. The effectiveness of Stediril may be compromised by failure to follow the dosage schedule: 1 pill daily for 21 days followed by a pill-free interval of 7 days when withdrawal bleeding occurs. Stediril should be taken at a regular time each day. If pills are missed for more than 48 hours, efficacy cannot be guaranteed. If vomiting occurs within 4 hours of pill ingestion, the pill should be replaced. Certain drugs, such as Rifadine, may affect the action of Stediril. Stediril should only be prescribed after a complete medical history and examination, including responding to any questions the patient may have. At a 3-month follow-up visit the patient's tolerance to the drug should be assessed by absence of various symptoms: psychological problems such as nervousness and irritibality that resemble those of pregnancy; skin problems such as acne or changes of pigmentation; periods of nausea that diminish in frequency after a few weeks; weight gain; bleeding problems; or signs of thromboembolic risk, such as headaches, unusual visual disturbances, or hypertension, which require immediate cessation of OC use. Because Stediril constitutes a risk to the fetus in case of unplanned pregnancy, the preliminary gynecological examination is mandatory and the pill should only be prescribed to women able to comply with dosage requirements. The pill should be stopped 6 weeks-3 months before pregnancy to allow the endometrium to regenerate. The carcinogenic role of the pill is frequently discussed but not conclusively proven. Follow-up visits should occur 3 and 6 months after beginning use and every year thereafter.