Does olive leaf extract affect the effectiveness of birth control pills?

Nobody really knows: People will try to sell many things, so watch out for products that claim to do beneficial things in lab studies, animal studies, very small studies, or studies that are not done in people like you. A phytonutrient is a plant-derived compound (chemical, protein, material) found to have positive health effects... but most are not studied, purified, nor quantified like real medicines have to be.