Hygiene deficiency causes type 1 (oral) halitosis. There are short and long-term studies on the anti-halitosis effect of mouth rinses but less knowledge on their instant effects. The aim of this study was to compare instant and freshness effects of 8 mouth rinses on type 1 halitosis. Ninety self-reported halitosis patients (19-58 y.o., median 31) were randomly divided into 9 groups. Cysteine (20 mM) challenge test was applied to obtain maximum halitosis level in the mouth of each patient. Single use of 8 different mouth rinses (R1-R8) and tap water (R0) were tested on each group (n=10). Afterward, patients were requested to score oral freshness effect of the mouth rinse on a 5-point scale (0, bad; 5, fresh). Minimum halitosis level was obtained by rinsing with 20 mMol ZnCL2. In each step, oral gas (organic, NH3, SO2, H2S, H2) concentrations were quantified by using a portable multi-gas detector (MX6, IndSci, US). The ANOVA or Kruskal Wallis tests were used to compare the quantitative measurements. R3 (Halitosil Zn) mouth rinse was found to be have the highest instant anti-halitosis effect while the R2 (Colgate plax) had the lowest. The sensation of freshness was highest in R7 (Oxyfresh power mouth rinse lemon-mint) and lowest in R8 (Signal expert protection). The freshness effect was not associated with the anti-halitosis effect (r= 0.185, p=0.608). Mouth rinses containing ZnCl2 without alcohol are instantly effective on halitosis. Mouth rinses containing ethyl and other alcohols (including glycol, sorbitol, menthol, eucalyptol, thymol, xylitol and eugenol) were found to be less effective on halitosis.