In the title compound {systematic name: 4-[2-({N-[(2S)-2-ammonio­propano­yl]glyc­yl}amino)­eth­yl]-1H-imidazol-3-ium dichloride}, C10H19N5O22+·2Cl-, the pseudo-tripeptide L-alanyl­glycyl­histamine is protonated at both the terminal amino group and the histidine N2 atom. The resulting positive charges are neutralized by two chloride anions. In the crystal, the organic cation adopts a twisted conformation about the CH2-CH2 bond of histamine and about the C-N bond in the main chain, stabilized by a short intra­molecular C-H...O contact. In the crystal, N+-H...O and N+-H...Cl- hydrogen bonds link the mol­ecules into infinite sheets parallel to the (100) plane. The stacking of these sheets along the a axis is supported by Namide-H...Cl- hydrogen bonds.