Abstract Natural disasters occur frequently in the country and civic authorities requisition medical aid from the Armed Forces for the succour of populations, with increasing regularity. The recent Orissa floods (2001) saw deployment of a Medical Team and the experiences of the team are discussed. Over a nine day period, 7450 cases were treated on site in medical aid posts established in flood affected areas. Of these patients , 4038 (54.20%) were affected by gastrointestinal illnesses (diarrhoea / acute gastroenteritis); 976 (13.10%) had suffered injuries and were treated accordingly; 2007 (26.94%) cases of respiratory infection were managed. 210 (2.82%) cases of undiagnosed fever were treated, and 18 (0.24%) cases of clinical malaria were diagnosed additionally. Skin and other infections comprised 186 (2.50%) cases of the total. Thus, this study provides a brief outline of the spectrum of illnesses that may be encountered in dealing with flood affected populations, for the benefit of planning for future humanitarian operations. The various stages of a disaster have been brought out, for an insight into the morbidity pattern in such deployments. The concept of ‘Health Emergencies in Large Populations’ is introduced in the discussion, for policy to be evolved. Public health is closely interlinked with disaster management, and the Army with its resource of trained specialists is geared for response in the face of disaster in a professional manner. Recommendations on dealing with future situations under such conditions of deployment have also been made.