Female rats displayed different patterns of attack to large and small male intruders into their home cages, as a function of ethanol dose levels. In confrontations with small male intruders, female attack increased significantly at 0.3 g/kg ethanol, declining to saline levels with higher doses (0.6 and 1.2 g/kg). Attack toward large intruders was (nonsignificantly) higher at 0.3 g/kg ethanol, and declined to significantly lower than saline levels with the higher ethanol doses. The attack increases seen with low ethanol doses came in the initial 5-min block of the 30 min test session, and did not persist. These findings suggest that low ethanol doses may especially increase overt aggression in situations in which the tendency to attack is only moderately inhibited by factors such as opponent size or the potential danger of retaliatory attack.