Negative externalities from consumption are common, ranging from the social and health costs of drinking, smoking or drug abuse, to the environmental damage caused by fossil fuel use. This column exploits the introduction of a price floor for alcohol in Scotland but not in other parts of the UK to assess the efficacy of a price floor for tackling the externalities associated with alcohol consumption. It shows that, if the external cost of an additional drink is at least moderately higher for heavy compared with lighter drinkers, then a price floor leads to larger welfare gains than a simple Pigouvian-style tax on ethanol. However, a tax system that taxes the ethanol in stronger drinks more heavily can do as well as a price floor at reducing heavy drinking while raising tax revenue.