Hello Thanks for the query to Health Care Magic. Femilon is an oral contraceptive , it contains a combination of hormones that help to stabilize irregular menstrual cycle particularly in patient having cysts in ovary , as in your case . Missing one dose is not a matter of concern. As you mentioned that you missed one dose , so next day take one tablet morning and one in the evening. Your treating doctor will likely want to come back after you have been on the femilon to see if the cyst is gone. At that time the doctor may suggest you stop using the medication or , if indicated , you may need to continue it for a bit longer. So missing only one dose is not concern. Try to take regularly. Hope this will be useful for you . Further if any question I will reply. Good luck.