Spanish flay, the stuff of fantasies, the magic aphrodisiac powder in legends of love -- and livestock breeding -- has been conquered by science.

For centuries the powder hs been obtained by grinding up an insect called the European blister beetle. And for more than a hundred years, scientists have been curious about the compound and have unsuccessfully tried to find a simple way to synthesize it in the laboratory.

They failed, until University of California chemists tried their hand with a new technique.

"Why did we do it? Well it had nothing to do with its biological properties. We did it because of the folklore," said Dr. William Dauben of the University of California at Berkeley, who produced the active chemical in Spanish fly by a new technique that uses high pressure to facilitate chemical reactions. "When an age-old problem exists in the field like this, you want to solve it for its own sake . . . it's the artist coming out in chemists."

However, Dauben said the technique will soon produce new and more efficient ways of making important chemicals such as antibiotics. And the substance, called cantharidin, has an immediate practical, commercial use. It cures warts.

Dermatologists use it for children's warts because it is less painful and works more slowly than other more potent and possibly dangerous common chemicals used to cure warts.

As for its legendary aphrodisiac properties, the stuff is overrated.

Its chief effect is to irritate and even blister the skin. "When it is ingested it can cause irritation in the urethra, and that can be stimulating," said dermatologist Gary Peck at the National Institutes of Health. Since the compound is extremely toxic, it can also cause severe blistering of the skin, inside and outside the body.

Peck recalled a case in which a man came into the hospital suffering from an overdose of Spanish fly. The man had a severely blistered esophagus.