A casein-free diet is a dietary approach that eliminates casein, which is a type of protein found in dairy products. The consumption of casein can trigger allergic reactions and digestive problems for some people. There are several synonyms for casein-free diet which include, dairy-free diet, lactose-free diet, milk-free diet, and non-dairy diet. People who follow a casein-free diet often replace dairy products with plant-based milk alternatives like almond milk, soy milk, or coconut milk. This diet can be challenging to follow, but it can be beneficial for people who have lactose intolerance, allergies or other digestive issues. A close collaboration with a nutritionist or healthcare professional is advised to ensure the adequate intake of essential nutrients.