Red: Attack, Strength, Defence, Ranged and Magic Orange: Smithing, Crafting, Fletching, Runecrafting, Cooking, Construction and Firemaking Yellow: Prayer, Agility, Slayer, Thieving and Hunter Brown: Woodcutting, Herblore, Farming, Fishing and Mining Generally you have to add 3 doses of the same color into one stew to boost the effect (i.e. 3 orange, 3 red, 3 brown, or 3 yellow)