Improbable research: Beware the perils of poppy seed bagels | Education | The Guardian
More foods that can throw off a drug test. In 1997 a patient tested positive for morphine, despite claims that they don't use morphine. After some queries, they discovered that the patient ate a lot of poppy seed bagels. The patient was asked to abstain from eating anything containing poppy seeds for a period two weeks. They then provided a urine sample, ate half a poppy-seed bagel under supervision, then provided a second urine sample. The second sample came up positive, as did tests at 24 and 48 hours.