hi,
Thanks for the query.

trigestrel pills are combined oral contraceptive pills,

Normally the effectiveness of pills will be affected by improper usage like not maintaining the time, missing pills etc.

Generally normal food will not interact with the effectiveness of pills,
Theoretically it is said that foods like,
licorice, yam, soy,
dairy products like milk from cattle treated with recombinant bovine growth hormone ,
Grapefruit belonging to citrus family,
Fish oil,
Herbs like hypericum, red clover, vitex etc,
Vitamins like Vit-c,
Drugs like carbamazepine, barbiturates, ampicillin etc
can decrease the effectiveness of pills,

Hope I have answered your query. I will be available to answer your follow up queries. If you are satisfied with all my answer, please rate the answer after closing the discussion.
Take care.

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