Tens of thousands of Cambodian refugees are entering Thailand. Many of the new arrivals are survivors of months of starvation and are critically ill with marasmus, kwashiorkor, beriberi, anemia, malaria, diarrhea, and respiratory diseases. With volunteer medical help, field hospitals are treating patients under primitive conditions that are gradually improving. Based on experience at the Sa Kaeo refugee camp, a brief survey of the nutritional and other diseases likely to be encountered is given for the potential volunteer who may be unfamiliar with tropical medicine.