This study used batch and online methods to accurately determine how much As, Cr, Se, Cd, Pb, Cu, Fe, and Zn can be leached from baby rice cereals into a baby’s body. Speciation analysis of the saliva and gastric juice leachates was conducted in order to further assess the risk associated with the continued consumption of baby rice cereal for infants. A simple 15-min chromatographic analysis successfully separated 8 species consisting of As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), As(V), Se(IV), Se(VI), (Cr(III)) and Cr(VI). Given that 95-100% As, 29-100% Cr, 62-100% Pb, 70-100% Se, 63-100% Cd, 36-100% Cu, 67-100% Fe, and 70-100% Zn were bio-accessible and the speciation analysis results showed all bio-accessible As and Se to be in the forms of As(V) and Se(VI) and 70-100% of Cr to be in the Cr(III) form, a variety of foods should be fed to infants rather than just baby rice cereal to ensure a well-balanced diet and less exposure to As at such a young age.