Objective This study assessed the effects of pictorial health warning labels (HWLs) and a linked media campaign in Mexico.

Methods Cross-sectional data were collected from a population-based sample of 1756 adult smokers, aged 18–55 years, during the initial implementation of pictorial HWLs, which some smokers had seen on cigarette packages while others had seen only the text-based HWLs. Exposure to the campaign and pictorial HWLs was assessed with aided recall methods, and other questions addressed attention and cognitive impact of HWLs, knowledge related to HWL and campaign content, and quit-related thoughts and behaviours. Logistic and linear regression models were estimated to determine associations between key outcomes and intervention exposure.

Results In bivariate and multivariate adjusted models, recall of pictorial HWLs and of the campaign were positively associated with greater attention to and cognitive impact of HWLs, whereas only pictorial HWL exposure was associated with having refrained from smoking due to HWLs. Both recall of pictorial HWLs and of the campaign were independently associated with greater knowledge of secondhand smoke harms and toxic tobacco constituents. Smokers who recalled only the pictorial HWLs were more likely to try to quit than smokers who recalled neither the pictorial HWLs nor the campaign (17% vs 6%, p<0.001).

Conclusions Consistent with other studies, adult smokers' exposure to new pictorial HWLs in Mexico was associated with psychosocial and behavioural responses related to quit behaviour. Exposure to the complementary media campaign was associated with independent additive effects on campaign-related knowledge, and it enhanced psychosocial responses to pictorial HWLs.