Food impaction is a common oral disease and a difficult problem for clinicians. The occurrence of food impaction not only brings inconvenience and pain to the patient’s eating, but also causes local caries, periodontal disease and bad breath. The earliest mention of the problem of food impaction was by Hirshfeld, who published a long article in JADA in 1930, which comprehensively discussed the concept of food impaction, its hazards, anatomical antiimpaction mechanism, classification, and etiology and treatment principles of each subcategory. This text has been the basis for all editions of the classical periodontology (clinical periodontology) as well as domestic textbooks on food impaction. Although the author’s definition of food impaction is very detailed, it is not easily understood, resulting in significant differences in the definition and classification of food impaction in China and abroad, which also directly affects clinical treatment. The definition of food impaction in China is divided into two narrative methods. One is the supplementary definition method, such as first defining that food is wedged into the gap between two adjacent teeth by occlusal pressure during mastication, which is called food impaction. Later, it is added that the movement of the lips, cheeks and tongue can press the food into the interdental space during eating, resulting in horizontal food impaction. The second is the full definition method, if the food enters the interdental space under the action of occlusal force or buccal and lingual muscles, it is called food impaction. The results of both descriptions are consistent, i.e., food impaction can come from either the sympathetic or buccolingual direction. This term may also be applied to a similar, although much less frequent, forcing of food into the buccal or lingual gingival crevices, but should be differentiated from the less forceful action of the tongue and the buccal parietes in depositing food in these spaces and crevices. In the latter action, the food produces no mechanical injury and can be easily removed by ordinary brushing and rinsing. The second sentence adds that the concept of food impaction also refers to a similar but rare situation in which food is pressed into the buccolingual gingival crevice, but it is important to distinguish food impaction from the deposition of food into the above-mentioned gap by the action of small forces on the buccolingual wall. The third sentence emphasizes that the buccolingual muscles do not mechanically damage food and that food is easily removed by brushing and rinsing. It is clear that the authors are emphasizing that the horizontal action of the buccolingual muscles does not cause food impaction, while domestic scholars have misinterpreted Hirshfeld’s intent and considered food impaction as the entry of food into the interdental space by the action of the buccolingual muscles.