Previous study in a short 14 day clinical trial at Thanyarak Institue, Pathumthani in Thailand [32] found a higher continuous abstinence rate (28.1%) in a VC supplemented group, compared to a control group of smokers (21.9%). However, the design of the study was difference from ours, with regards to the preparation of the VC juice, as well as the intake of the juice. In the present study, our subjects were asked to drink the VC juice prior to each time they planned on smoking. They were instructed to keep the condensed VC juice in the mouth for 1-2 seconds prior to being swallowed.