Poppy seeds are highly nutritious, and less allergenic than many other seeds and nuts. Allergy (type 1 hypersensitivity) to poppy seeds is very rare, but has been reported and can cause anaphylaxis.
Poppy seeds are a potential source of anti-cancer drugs.
False positive drug tests
Although the drug opium is produced by "milking" latex from the unripe fruits ("seed pods") rather than from the seeds, all parts of the plant can contain or carry the opium alkaloids, especially morphine and codeine. This means that eating foods (e.g., muffins) that contain poppy seeds can result in a false positive for opiates in a drug test. The test is true positive in that it indicates the presence of the drug correctly; it is false only in the sense that the drug was not taken in the typical manner of abuse.