Parietal or oxyntic cells secrete two important components, i.e. $\mathrm{HCl}$ and castle intrinsic factor.

$\mathrm{HCl}$ is responsible for making the stomach environment acidic in nature ($\mathrm{pH} 1-3$) and activation of pepsinogen to pepsin.

Castle intrinsic factor is essential for absorption of vitamin ${\mathrm{B}}_{12}$.