You should never take medicine you are unsure of.
Dale's back is killing him and his roommate offers him some pills, without telling him what it is.
Dale doesn't want to go to the store to get medication.
Dale decides not to take the unknown pill and asks his roommate to go to the store get some Advil for him instead.
Dale takes his roommate's pill, even though he has no idea what it is.
Dale feels much better after taking the Advil.
Dale has a violent reaction to the pill.