Unlucky in love, chemist Paul Matthews visits gypsy Madame Rosa for help. Quickly realizing he is a hopeless nerd, she gifts him with Love Potion No. 8, which makes anyone who wears it irresistible to the opposite sex for four hours. Paul and animal psychologist coworker Diane Farrow decide to test it on themselves. The awkward pair suddenly find themselves alluring to anyone they approach, but soon realize they are most attracted to each other. Two scientists who are hopeless with the opposite sex experiment with a substance that makes them irresistible to anyone who hears them speak.