BACKGROUND: Green tobacco sickness (GTS) is a highly prevalent occupational illness among tobacco workers. Working in wet tobacco is a major risk factor for GTS. Little is known about preventing GTS. This analysis examines possible GTS preventive measures. METHODS: Data were collected from 36 patients with GTS and 40 controls who presented at clinics in eastern North Carolina in 1999 and 2000. Each participant completed an interview that included questions about their personal characteristics, work characteristics, and GTS risk factors. RESULTS: Participants were Mexican men. Those with GTS were much less likely to have worn rain suits while working in wet tobacco and more likely to be in the United States on a work contract. CONCLUSIONS: Wearing a rain suit while working in wet tobacco can significantly reduce the risk of GTS among tobacco workers. Care must be taken that farmworkers do not have heat stress from wearing rain suits.