食物不耐症（food intolerances）是指因为食物、饮料、食品添加剂或是食物中成份产生的有害反应，一般会在食用食物之后一段时间才会出现，有害反应会在一个或多个器官或是系统出现，但一般是指食物过敏以外的反应。除了食物过敏外，还有其他种类食物敏感（Food Sensitivities）的症状，而和食物过敏不同的，这些症状都是在食用食物之后一段时间才会出现的超敏反应。

食物不耐症可以依其机制来分类，食物不耐症可能是因为缺乏消化特定食物时需要的化合物或是酵素而产生，例如遗传性果糖不耐症，也有可能是因为身体无法吸收特定营素所造成，例如果糖吸收不良。食物不耐症可以是因为食物中自然存在的化学物质而造成的，例如水杨酸敏感。从植物提炼的药物（例如阿斯匹灵）也会引起这类不耐症。也可能是无IgE介导的免疫反应的结果。

Food intolerance (or non-allergic food hypersensitivity) is a detrimental reaction, often delayed, to a food, beverage, food additive, or compound found in foods that produces symptoms in one or more body organs and systems, but generally refers to reactions other than food allergy. Food allergies are immune reactions, involving mast cells in which food triggers release of mast cell mediators, such as histamine when the food allergen binds to pre-formed IgE antibodies already bound to the mast cell. This mechanism causes allergies to typically give immediate reaction (a few minutes to a few hours) to foods. There are numerous causes for other types of food sensitivities, most of which, in contrast to food allergies, cause delayed hypersensitivity reactions to the food.