To provide a label printing apparatus and an allergic substance display method using a label, whereby even children and weak-sighted people can easily aware whether or not food contains allergy substances and information about allergy substances can be checked easily even after the food is taken out of a container.

An allergic substance table is prepared, and a first label 10A and a second label 10B on both of which print data are printed are stuck to the front and the back of a packaging container for food. In this case, an allergic substance table is provided, and the first label 10A attached to the food front side and the second label 10B attached to the food back side are prepared, on which allergy information about allergic substances can be displayed as part of print data. Optically readable codes for specifying food can be printed on the first label 10A and the second label 10B.