In the second quarter of 2003,four incidents of collective food poisoning occurred consecutively in three counties of Linxia Hui autonomous prefecture,Gansu Province.The incidents broke out in 3 religious activities and 1 family meeting,in which a total of 446 people of various ages took part and ate the causative meal.Symptoms of poisoning appeared in 273(61.21%) of them,and mostly in young people under the age of 30.Bacteriological culture revealed Bacillus Proteus from the remained foods and victims' feces in all the 4 incidents.The frequency of collective food poisoning in this prefecture indicated the urgency to reinforce the spread of the knowledge of food safety and enhance the supervision of the collective dining in religious activities.