Salted tea prepared in Kashmir by adding sodium bicarbonate shows high methylating activity (equivalent to 3 p.p.m.N-methylnitrosourea) uponin vitronitrosation. Pure caffeine treated under conditions of the tea preparation formed caffeidine and caffeidine add. We report here the formation of two new compounds, mononitrosocaffeidine, an asymmetric nitrosamine, and dinitrosocaffeidine, aN-nitrosamide, onin vitronitrosation of caffeidine. Mononitrosocaffeidine is also found after nitrosation of the typical Kashmir tea. The nitrosation of caffeidine acid producedN,N′-dimethyl-parabanic acid, mononitrosocaffeidine andN,N′-dimethyl-N-nitrosourea. In view of the well-known structure-activity relationships of theseN-nitroso compounds, their possible endogenous formation due to high consumption of salted tea may be a critical risk factor for the high occurrence of oesophageal and gastric cancers in Kash