Egg yolks do not cause hairballs in cats. Egg yolks are a very nutritious food that can supplement a cat's diet and help improve the appearance of its fur, making it shiny and smooth. However, they do not have the effect of removing hairballs. Furthermore, cats should not be fed too many egg yolks, as they are high in cholesterol, and excessive consumption can easily cause them to experience heatiness or other health problems. 
How to apply hairball remedy to a cat:
1. Owners can regularly brush their cat's fur to reduce the amount of fur the cat ingests.
2. Feeding cats cat grass can induce vomiting and help them expel hairballs from their bodies.
3. Feeding your cat hairball remedy can help it expel hair from its body.
4. You can feed your cat some fruits and vegetables. Fruits and vegetables contain a lot of fiber and vitamins, which can also help your cat expel some of the hair.
