Bad Trip and Health Down pills will turn into I Found Pills when Isaac is at one heart.
Neutral pills will not have a secondary effect.
If any stat down pills were taken before picking up the item, a damage increase is given for each pill.
Pills are only converted while held by a character with False PHD. For example: If playing as Jacob and Esau and Jacob has this item, pills that got converted into 'bad' pills like a Tears Down pill can be given to Esau to convert them back into a Tears Up pill, or whatever the pill was originally.
Losing the item by either dropping it as Tainted Isaac or re-rolling it via D4, etc., causes the damage buffs given to be removed.
A Pony/White Pony: Effectively converts all Speed Down pills into Damage Up as long as one of the ponies are being held, since they will always give a minimum of 1.5 speed.