Struempler R E
J Anal Toxicol. 1987 May-Jun;11(3):97-9. doi: 10.1093/jat/11.3.97.
After the ingestion of three poppy-seed bagels, the following codeine and morphine concentrations were determined in the urine: 214 ng/mL codeine and 2797 ng/mL morphine at 3 h, and 16 ng/mL codeine and 676 ng/mL morphine at 22 h. This work indicates that a positive finding of codeine or morphine in the urine of an individual does not necessarily indicate heroin, morphine, or codeine use.