All you connoisseurs who lament that new versions of old classics—the Corvette, Astroturf, metal bats—just do not measure up to the original can cross one example off your list: absinthe.

The bitter green liqueur made from wormwood was for decades the toast of Europe, imbibed by the likes of van Gogh, Degas, Toulouse-Lautrec and Picasso to, it was believed, spur their creativity. For absinthe was deemed more drug than drink: thujone, a natural essence found in common wormwood (Artemisia absinthium L.) and Roman wormwood (Artemisia pontica L.) that was widely believed to be its active ingredient, induces convulsions like those suffered by people with epilepsy, and was thought to account for absinthe’s supposedly mind-altering properties. Thujone was thought to explain absinthe’s reputation as a “green fairy” and a “green muse.” (The original absinthe also contained green anise, Pimpinella anisum L.; hyssop, Hyssopus officinalis L.; lemon balm, Melissa officinalis L. and Florence fennel, Foeniculum vulgare Mill.)

I couldn’t avoid all those “supposedly”s and “thought to”s in the paragraph above: it turns out that there had been only a single actual test of how much thujone classic absinthe contained. By “classic,” I mean the version available throughout the 19^th century, before first Switzerland and then most of Europe banned it beginning in 1908. (Spain and some other countries never banned it, however.) Now, though, a team of scientists has managed to get their hands on 13 unopened bottles of the original, pre-ban absinthe, produced in France before 1915. They find that the stuff contains too little thujone to alter anyone’s mind—but more than enough alcohol to do so: the absinthe contained 70 percent alcohol, making it 140-proof, compared to proofs of 80 to 100 characteristic of most gin, vodka and whiskey. They’ll report their findings in the May 14 issue of the Journal of Agricultural and Food Chemistry.

Starting in December 2004, the scientists began locating samples of pre-ban absinthe, eventually finding unopened, uncontaminated bottles in France, Switzerland, Spain, Italy, The Netherlands, and the U.S. Earlier, they had made some theoretical calculations about how much thujone absinthe makers were likely to get out of the wormwood they used, concluding that “for typical French and Swiss 19th century recipes” the thujone content probably ranged from zero (if thujone-free wormwood was used) to 76 milligrams per liter (if oil-rich varieties with high thujone concentrations were used). The average would have been around 17–23 mg/L.

Their findings matched their expectations. Analyses of the 13 pre-ban bottles showed thujone concentrations of 0.5 and 48.3 mg/L, with an average of 25.4 20.3 mg/L. The highest was 48.3 mg/L, in a Pernod Fils absinthe.

What do the numbers mean? If you imbibed one whole liter of the high-thujone Pernod Fils, you would get about 0.8 mg of thujone per kilogram of body weight if you weighed 60 kg (132 pounds)—less if you weighed more, more if you weighed less. But “even this unrealistically high intake of alcohol produces thujone concentrations below the ‘no observed effects level’ of 5 mg/kg bodyweight.” That is, glugging an entire liter—something even Toulouse-Lautrec rarely managed—would still leave you at less than 16 percent of the amount found in tests to produce mind-altering effects.

For what it’s worth, the thujone levels in these pre-ban absinthes were about the same as those in modern absinthe, which has been produced since 1988, when the European Union lifted its ban. “All things considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome of absinthism,” said one of the scientists. Classic absinthe may have been a psychedelic substance, but only because quaffing anything that’s 70 percent alcohol tends to be.