The present study was conducted to compare short-term treatment response patterns following scaling and root planing in smoking and non-smoking Chinese patients with untreated adult periodontitis. Thirteen smokers and twelve periodontally matched non-smokers with untreated advanced adult periodontitis were evaluated prior to and at one, three, and six months after scaling and root planing. Probing depths (PD), probing attachment level (PAL) and gingival height (GH) were assessed at clinically healthy, gingivitis and periodontitis sites. PD and PAL were measured using electronic Florida pocket and disk probes, respectively. Non-smokers consistently showed significant gingival shrinkage in gingivitis sites, whereas smokers had no significant change in GH. In periodontitis sites, both groups exhibited significant decreases in PD (p < 0.001) at one month, and a greater reduction of PD was found in non-smokers than in smokers (p < 0.05), the difference being most notable at three months (2.4 +/- 0.2 mm vs. 1.1 +/- 0.3 mm, p < 0.001). Non-smokers showed a consistent gain of attachment in periodontitis sites from 0.5 +/- 0.2 mm at one month (p < 0.05) to 1.2 +/- 0.3 mm at six months (p < 0.001), whereas no significant gain of attachment was found in smokers until six months (0.5 +/- 0.2 mm; p < 0.05). Overall, the reduction of PD positively correlated with baseline PD in both smokers (p < 0.01) and non-smokers (p < 0.001), but when only the sites with an initial PD > or = 5 mm were considered, such a significant correlation was found only in non-smokers (p < 0.05). A positive correlation was also found between the change in PAL and baseline PD solely in non-smokers (p < 0.05). This study indicates that smokers have different treatment response patterns and healing dynamics compared to non-smokers following scaling and root planing, suggesting that for smoking patients a more intensive treatment regimen is needed for a better treatment outcome and reduced risk for further periodontal disease progression.