BACKGROUND: Processed meat has been related to the risk of digestive tract neoplasms but the evidence remains inconclusive. We examined data from a network of case-control studies conducted between 1992 and 2002 in the Swiss Canton of Vaud. PATIENTS AND METHODS: We studied 316 patients with incident, histologically confirmed oral and pharyngeal cancer, 138 patients with oesophageal cancer, 91 patients with laryngeal cancer and 323 patients with colorectal cancer. Controls were 1271 subjects admitted to the same hospital for a wide spectrum of acute non-neoplastic conditions, unrelated to long-term modification of diet. RESULTS: There were strong direct trends in risk between consumption of processed meat and the various neoplasms considered: the multivariate odds ratios for the highest quartile of intake compared to the lowest were 4.7 for oral and pharyngeal cancer, 4.5 for oesophageal cancer, 3.4 for laryngeal cancer and 2.5 for colorectal cancer. The association was stronger in younger subjects, in moderate drinkers and in non-smokers. CONCLUSION: Processed meat represents a strong indicator of unfavourable diet for digestive tract and laryngeal cancer risk in this population. [authors]