In many novels we have alchemist who make miracles pills and potions, but is there a difference between the two. In most cultivation novels its pills, but game novels with alchemist make potions. Is it just the author for their novels have alchemy be pills, or alchemy be potion?
Pill popping for xianxia cuz their culture. Potion chugging for magicland cuz their culture Yup, it is a culture thing. They are exactly the same thing, just like of you want your medicine to be pill or liquid form.
I haven't seen many novels that have both even tho they are both called alchemy or pharmaceutical. A potions tho tends to have more side effect in most novel than the pill counterpart at least when you see them they are usually in magic oriented novels while cultivation novel have all kinds of pills most of them work more towards miracle effects strength/cleansing/curing. when taking cultivation pills that increase strength they do have an immediate effect that puts strain on the cultivator, but once they have endured their strength increases by many fold. For potions it's usually an effect when taking the potion and an after effect that usually leaves some sort of negative effect that the character must later find a way to remove. there are a few novel with exceptions I am currently reading Another world's versatile craftsman which has many potions with no side effect which is rare from all the other's I have read. If I had to pick the cultivators pill tend to be more miraculous while the potions tend to be more realistic side as they usually increase strength for a time limit or even if they do permanently increase strength it's not by a lot. the pill counterpart tend to completely transform your strength while paying an immediate price of having to endure tremendous pain and test of willpower, but the pay out is more than 100 times.
The only novels that usually have both potions and pills are ones that have to do with healers or healing potions and pills with different ones having different effects
Potions are easier to make. Pills are easier to take. For efficiency purposes, it depends on the ingredients and purpose which method is better and which is worse, but most medicines should more or less work either way. So it's up to the author how fantasy medicines work.