這些東東網上一大堆，給你找了幾個。也回敬過小問題，就說酒精過敏吧，你能否讓他們今後接觸酒精後不過敏？

http://baike.baidu.com/view/921216.htm

http://en.wikipedia.org/wiki/Wheat_allergy

http://www.centerforfoodallergies.com/milk_allergies.htm
What Causes a Milk Allergy?
Most likely it is a genetic condition. In the big picture, humans have only recently introduced cow’s milk into the diet, so it’s not surprising that the immune system doesn’t always recognize it as a friendly substance.

https://en.wikipedia.org/wiki/Food_allergy