While viewing an operation on "Seinfeld," Kramer and Jerry drop a Junior Mint into the body. The incident occurs in "The Junior Mint," the 60th episode of the series and the 21st episode of its fourth season.
Jerry and Kramer watch a surgeon operate on Roy, an artist who was once romantically involved with Elaine. Kramer is eating Junior Mints in the hospital viewing gallery and accidentally drops one into the open surgical area. The mint later appears to improve Roy's condition, creating the episode's central comic mystery.
Junior Mints are small round candies with a dark-chocolate coating and a peppermint center. The brand was introduced in 1949 by James O. Welch Company and was named after the Broadway play Junior Miss. The candy is often confused with similarly shaped chocolate-mint products, but the episode specifically identifies Junior Mints.