- "Does this have lemon in it?"
- —Meredith Rodney McKay
A lemon is a citrus fruit that is known to have grown on Earth. Due to the fruit's citric nature, Dr. Rodney McKay believes he is deathly allergic to this fruit. Lt. Colonel John Sheppard has kept a lemon with him at all times, saying that "it's just a comfort to know it's there." Lieutenant Colonel Cameron Mitchell used a lemon to "threaten" McKay. In 2007, McKay also instructed the people of his nation Geldar that lemons were a bad thing. (SG1: "The Pegasus Project", SGA: "The Game")