Eating poppy seeds can introduce opiates into your body. Those little seeds come from the same plant, the opium poppy ( Papaver somniferum), that is used to make heroin. And the seeds themselves actually contain trace amounts of the opiates. Yep, these innocent-looking seeds: For the record, the seeds themselves are not used to make opium.

Poppy seeds don’t naturally contain opium compounds but may become contaminated with them during harvesting or as a result of pest damage ( 13 ). Thus, before reaching supermarket shelves, poppy seeds are usually cleaned to get rid of any opium alkaloids with which they may have come into contact.