Yes plums can make you poop if you eat enough of the plums.
Plums are high in fiber content and are higher in fiber content than apples or other fruits.
Prunes are commonly used to help get peoples bowels moving and what prunes are really are just a certain type of plums that are dried.
So if you eat enough of the plums it can help make you poop and get your bowels moving.
Plums are also very healthy for you to eat as well so it can make you poop plus provide you with needed vitamins as well as nutrients that our bodies need to stay healthy.