Mass gatherings are an increasingly common feature of modern society. However, descriptive papers that focus on a single event or event type, dominate the literature, and, while these contribute to our understanding of the patient care required at such events, they do not provide an adequate analysis of the health effects of the mass-gathering phenomenon itself. This paper argues for the development of conceptual models and a research template for mass-gathering research. The development of theory and conceptual models would promote a better understanding of the health effects of mass gatherings. Two preliminary conceptual models are presented as a means to encourage further debate about the dominant influences on the health of people where crowds gather and to promote less superficial forms of analysis of the research data. These conceptual models are based on the idea that mass-gathering health can be understood as an inter-relationship between three domains: (1) the biomedical; (2) the environmental; and (3) the psychosocial. Key features influence the rate of injury and illness and characterize each domain. These key features are more or less well-understood and combine to produce an effect--the patient presentation rate, and a response--the health plan. A new element, the latent potential for injury and illness, is introduced as a mechanism for describing a biomedical precursor state important in assessing health risk during mass gatherings.