The Advisory Council on the Misuse of Drugs have just published a literature review on the social harms of khat use.  Key findings:

1. The review found a general lack of robust evidence on the link between khat use and social harms.
2. Reported social harms associated with khat remain a concern among the UK’s immigrant Somali community, yet beyond often contradictory anecdotal statements, this review found no evidence to show a causal relationship between khat and the various social harms for which its consumption is supposedly responsible.
3. Inferences about khat’s social harms have largely been drawn from the experience of the Somali population, as less research has been undertaken on other communities who are also consumers of khat.
4. As well as khat, many other variables might contribute to the social problems confronting the relevant communities, i.e. the effects of civil war, displacement, gender relations, and problems of integration. These need to be more fully considered in any further research.
5. Legislating against khat in Europe and North America has had little success in curbing demand and has taken place with little consideration of evidence. In those countries where the greatest evidence on khat use has been compiled (the UK, the Netherlands and Australia), import and consumption are still permitted, albeit under the control of a permit system in the case of Australia.

Hopefully this review of the evidence is enough to prevent any moves to criminalize khat sales.  See previous discussions here and here.