First, the worms are in bottles of ‘Mezcal’, not Tequila. Back in the 1940’s, some American-bottled brands of Mezcal came up with a marketing ploy. Stemming from the myth that the worm possessed magical and aphrodisiac properties, they put it in their bottles of Mezcal to impress the gringos and boost sales. The myth persists today! And even though the little worm might soak up a little alcohol, eating it has no noticeable effect on people.