From Tandem comes a piece on carrots, in which we read this:

Carrots were known to the Ancient Greeks and Romans who, believe it or not, thought the carrot was an aphrodisiac of sorts. One believer in the carrot's ability to increase sexual stamina was Roman Emperor Caligula, who forced his Roman senators to feast on the veggie.

Hmmmm ... the first page that pops up with Google in regards to carrots and Caligula says:

Native to Afghanistan, carrots were known to both the Greeks and Romans. In fact, the Greeks called the carrot "Philtron" and used it as a love medicine--making men more ardent and women more yielding. The Roman emperor Caligula, believing these stories, forced the whole Roman Senate to eat carrots so he could see them "in rut like wild beasts."

Well, it doesn't mean that in my L&S ... this sounds like some corruption of that strange word 'philtre' that I used to wonder about as an undergrad (coffee philtres?). Another from another site, with another variation:

And a carrot fact from the 1st century: Emperor Caligula, “a renowned crazed megalomaniac given to capricious cruelty and harebrained schemes, including [making] his horse, Incitatus, a consul, ... is purported to have once fed the entire Roman Senate a banquet only of carrot dishes.”

Now comes the obvious ... does anyone have a source for this claim? I can't find anything related ...