Some questions about birth control pills [View All]

[JVS]

I was watching TV and saw a commercial for a birth control patch in which the main selling point is not having to remember to take a pill every day. I remembered back to health class in jr. high when our teacher told us that most of the pills in a birth control packet were placebos that are included to make the taking of pills a daily routine, lest it be forgotten when it counts, and that there were only several pills per month with active ingredients. So my questions are as follows: is/was (may have changed since then) my health teacher correct? If so are the active pills marked differently from the placebos so that if one were to miss a day they could check and see that it was only a placebo, or similarly one would notice an important day coming up?