The present research was set up to verify whether the chemical products used in lemon production (from cultivation until packaging) have a bactericidal or a bacteriostatic ability against Vibrio cholerae O1. The studied products were: copper oxychloride, benomil (a carbamate), active chlorine, sodium-o-phenylphenoate, guazatine (a polyamine mixture), imazalil (an imidazole) and lemon peel. The latter was studied with and without treatment using the above mentioned chemicals. Different dilutions of these products were tried out with varying exposure times against the bacterium V. cholerae Serogroup O1, Biotype E1 Tor, Serotype Inaba. The concentrations of the microorganism ranged from 10(2) to 10(8) CFU ml-1, the latter one being considered an infectious dose. The following results were obtained: 1) active chlorine (chlorinated water) showed bactericidal activity at concentrations of 50, 100 and 200 ppm after 10 min of exposure time, 2) copper oxychloride, sodium-o-phenylphenoate, guazatine and imazalil showed bactericidal activity against V. cholerae at concentrations of 10(2) and 10(4) CFU ml-1, 3) due to the fact that during its cultivation the fruit is successively sprayed with several chemical products, it could be that the result of the successive treatments is superior to the result of a repeated treatment with each of the individual products. This consideration should be taken into account when evaluating the eventual protection of the lemon.