There is a shelf to the west with 4 potion types lined up... The correct sequence is <span class='standouttext'>Spoiler : </span><span class='spoiler'>red, green, blue, yellow</span> (highlight the text to read).
In the next room, save before trying each chest. What you get is determined by how many attempts you need (max 2 tries) to get the correct colour. There are runes on the wall to give you a hint.
