Loiseau the pharmacist mistakenly mixes potassium cyanide into a batch of cough syrup and sells five bottles. With horror he discovers his mistake and sets out to find the buyers. He finds only four. The fifth, not a regular customer, comes back to the pharmacy...

Fernand Ledoux
Pharmacist Adrien Loiseau

Georges Lannes
Ceccaldi
Colette Richard
Young bride

Maurice Schutz
Loiseau's stepfather
Christine Hayrel
Horsewoman
Mona Dol
Gossip
Jacky Pasquero
Ceccaldi son
Jean-Marc Lambert
Young groom

René Blancard
Philippe Chauvieux
Charles Lavialle
Catcher
France Noël
Régine Talma
Christine Gil
Claude Assemat

François Joux
Alfred Bouchard