Disadvantages of using rodenticides include:

1. They can contaminate the soil and water.
2. They can kill non-target animals if they eat the bait.
3. They can be harmful to people if ingested or if they come into contact with the skin.
4. If not used properly, they can be a danger to public health and the environment.
5. They can be expensive.
6. They may not be effective in all situations.
7. They can pose a risk to pets and children if not used properly.