Research chemist Barnaby Fulton works on a fountain of youth pill for a chemical company. One of the labs chimps gets loose in the laboratory and mixes chemicals, but then pours the mix into the water cooler. When trying one of his own samples, washed down with water from the cooler, Fulton begins to act just like a twenty-year-old and believes his potion is working. Soon his wife and boss are also behaving like children.
Alternative titles: Monkey Business | Be Your Age | Vitaminas para el amor | Liebling, ich werde jünger | De knuppel in het apenhok | Chérie, je me sens rajeunir | O Inventor da Mocidade | Маймунджилъци | 妙药春情 | Majmunska posla | Joven otra vez | Omlazovací prostředek | Foryngelseskuren | Rakas, minä nuorrun | O varnavas, i Edwina, i maimou kai to bogomolec | Ο Βαρνάβας, η Εντβίνα, η μαϊμού και το Μπογκόμολετς | Gyanús dolog | Il magnifico scherzo | Mon’ki bijinesu | モンキー・ビジネス | Isdaiga | Me siento rejuvenecer | Apestreker | Małpia kuracja | A Culpa Foi do Macaco | Afacere idiotică | Afaceri încurcate | Обезьяньи проделки | Obez’yan’i prodelki | Åh, en sån fräckis | Föryngringsprofessorn | 妙藥春情 | Tehlikeli oyun | Мавпині витівки | Howard Hawks’ Monkey Business | Darling I Am Growing Younger