Substitute poison for healthy food.
Substitute poison with healthy food.
The first means you take away healthy food and give poison. The later means you take away poison and give healthy food.
[1] Except that "replace X for Y" sounds weird, except in the common phrase "replace like for like" (and probably some others!).
Substitute poison for healthy food.
Substitute poison with healthy food.
The first means you take away healthy food and give poison. The later means you take away poison and give healthy food.
[1] Except that "replace X for Y" sounds weird, except in the common phrase "replace like for like" (and probably some others!).