About 1,000 years after acquiring the habit, the people in the corner of the Arabian Peninsula that forms Yemen have never been more hooked.

More than cigarettes, more than the illicit whisky found in many middle-class households, more than the mouthwatering kebabs and roasted Red Sea fish that are the favored fare in the bazaars, what holds this devout Muslim nation of 16 million people in thrall is the mildly narcotic effect that comes from chewing the tender green leaves known as khat (pronounced GAHT).

Surveys show that more Yemenis than ever -- at least 80 percent of men, about 60 percent of women and increasing numbers of children under 10 -- settle down on most afternoons to a habit that ancient scripts recorded among merchants and religious mystics as early as the 10th century A.D. Plucking the choicest leaves off a bundle of khat branches, aficionados chew relentlessly into the evening, until the keenest of them have tennis-ball-sized gobs of leaves in their cheeks, and the appearance of glassy-eyed Popeyes.

In a country where many people live off incomes of $100 a month or less, some of the poorest families cheerfully admit to spending 50 percent of their earnings on khat. The Government acknowledges that 40 percent of the country's irrigated farming land is given over to growing khat shrubs and trees.