I would like to know what decreases the effect of a contraceptive method. Any particular class of medication? What are they? Vomiting?

Hello Ma'am,

There are relatively few drugs that decrease the effectiveness of the pill. Those that do are often stimulants for the liver, the place where the pill is metabolized by the body.

I'm thinking of St. John's wort, a natural health product, among other things.

Also, vomiting 60 minutes after taking the pill greatly decreases its effectiveness.

Finally, the woman who has diarrhea several times a day could have decreased effectiveness, as the pill may not have had time to be fully absorbed.

Happy day,

Alexander