Thank you for your feedback!
I'll start working on a more fleshed out version soon featuring more ingredients, effects, contracts, a few more mechanics and a story.
The remove button for ingredients is a good idea. Originally I didn't include it since I saw the issue with the effects showing, but showing all the effects upon poison creation is a lot better idea.
Also the music wasn't made by me. I got the track called "Sewers" from a Humble Bundle content bundle I bought from gamedevmarket.net called "Dungeon Music". But I'll make sure to add my own tracks one day.
Fun fact: this was my first Ren'Py game. I kinda fell in love with the engine now.