AbstractThe chemical and biological properties of poppy seed (Papaver somniferum) were studied to evaluate its possible role as a complement to or replacement for rapeseed in Sweden. A white variety of the seed contained 40% crude oil and 27% protein (N × 6.25), while a blue variety contained 33% oil and 21% protein. The amino acid composition of the two varieties were similar with chemical score values of 60 and 66, respectively. A meal was prepared by hydraulic pressing at room temperature. The protein efficiency ratio for this meal in rats was 2.34. A protein concentrate was prepared from the poppy seed meal by alkaline water extraction followed by iso‐electric precipitation of protein. The freeze‐dried precipitate contained 70% protein and 18% fat. Available lysine was the limiting amino acid in the protein concentrate.