the one where Phoebe gets sick

Meanwhile, poor and unemployed Phoebe needs her singing at Central Perk to keep her spirits up during this difficult time, when, to cap matters, she also catches a cold. When she projects her first notes on the microphone, she falls in love with her new, sick, sexy voice. However, the new voice doesn t last long when she heals from her cold. When Monica catches a cold too, Phoebe accuses her of stealing it and does anything in her power to get her cold back, including stealing Monica s coldcovered napkins and licking her halffinished noodle soup, but this does nothing for her. When she catches Gunther sneezing at the coffeehouse, Phoebe kisses him fully on the mouth, which gives her a cold and a sexy voice again. At the end of the episode, Gunther apologizes to Rachel for kissing Phoebe on the lips. Thoroughly confused, Rachel forgives him.