The Rejuvenating Potion is a potion made by Senbei Norimaki in the chapter "Goo Ga Senbei". The recipe is worms (x3), milk (200 cL), sugar (x1.5), Gamera egg (x2), plum (x3), Orovitam D (x1), and salt.
Senbei uses this potion when he falls to the ground, thinking he has become too old seduce Midori Yamabuki. After drinking it, he becomes a baby again, but retains his personality. Arale Norimaki finds him and tells that Midori will come to their house. Senbei is at first sad to learn that he will not be an adult to greet the woman he loves in his house, but becomes happy when he realizes that he can use his baby form to watch and abuse her. He looks under her dress, and sees her naked when she takes a bath with the kids. Unfortunately, he ends up beaten when he reverts back to his adult form while sleeping with her.