Background Alcohol, aggression and assault injury are strongly associated with popular sporting events, but mediating factors are not clear.

Aims To explore aggression, happiness and plans to consume alcohol among spectators before and spectators after sports matches.

Methods Cross-sectional surveys of male rugby football fans at an international stadium generated four groups: a pre-match group of 111 men, and three post-match groups of supporters, 17 whose team had won, 23 whose team had lost and 46 whose team had drawn. Consenting participants were assessed using the assault sub-scale of the Buss-Durkee Hostility Inventory, on a self-rating of happiness (Likert scale), for planned alcohol consumption and demographic variables. Pre- and post-match group mean responses were compared.

Results Analyses were performed on 197 male spectators (mean age 42 years). Spectators in ‘win’ (z = 2.63, p < 0.01) and ‘draw’ (z = 2.76, p < 0.01) groups rated themselves as more aggressive than those in the pre-game group, but those in the losing group did not (z = −0.03, p > 0.05). No differences, however, were observed between pre-match, ‘win’, ‘draw’ or ‘lose’ groups on the decision to drink after the match. Winning did not increase happiness (t = 0.25, p > 0.05), but losing (t = 2.09, p < 0.05) or drawing (t = 7.64, p < 0.001) decreased it.

Conclusions This study suggests that team success but not failure may increase aggression among supporters, and that aggression, not celebration, drives post-match alcohol consumption. Losing and drawing decreased happiness but winning did not increase it. Better understanding of pathways to violence in these circumstances will pave the way for more effective prevention and management strategies. Copyright © 2007 John Wiley & Sons, Ltd.