What happens when the Gauls convey the antidote to the Romans?

When the Gauls convey the antidote to the Romans, Crismus Bonus doubts the validity of the antidote. Asterix drinks it and points out that his mustache is not growing. The Romans drink the antidote, but when their hair stops growing, Crismus Bonus orders the guards to attack Asterix and Getafix. Luckily, Asterix has already drank the strength potion, and he easily beats the Romans.