Any farang who wonders why a tiny drop of alcohol triggers such dramatic reactions among some Thais now has his answer from scientists at the Kunming Institute of Zoology in Yunnan in China.

Their research into the distribution of the ‘Asian flush‘ – the widespread hypersensitivity to alcohol in the Far East – has fingered the Pai-Yuai tribe of south China, who apparently spread an ‘atypical ALDH2487Lys allele’ across the region.

For carriers of the gene, a sip of alcohol bring an instant hangover along with the distinctive red face known variously as the Oriental Flush, the Asian Flush or the Asian Glow.

The buildup of acetaldehyde that fires this reaction is a serious impediment to social drinking but – on the positive side – offers protection from alcoholism. The drug disulfiram (Antabuse) mimics this response to keep alcoholics off the juice.

By the standards of the region, Thailand is relatively free of red-faced drinkers. However, the Pai-Yuai tribe did make it to the north of the country, leaving their ancestral mark on its inhabitants.

Many ALDH2-deficient drinkers can benefit from taking heartburn medicine an hour before they hit the sauce. An alternative strategy could be to binge out on carbohydrates.