Poppy seeds are tiny blue-grey oily seeds. They are about 1 mm across at most.
Poppy seeds can be added to almost any bread recipe by sprinkling or rolling the dough in the seeds before baking it, much as one might do for sesame seeds. Poppy seeds are especially popular on bagels.
Eating poppy seeds can cause people to fail drug tests.
According Encyclopædia Britannica Online: "tiny dried seed of the opium poppy, used as food, food flavouring, and the source of poppy-seed oil. Poppy seeds have no narcotic properties, because the fluid contained in the bud that becomes opium is present only before the seeds are fully formed."
However it is proven that eating poppy seeds does give false positives on drug tests.