There are plants, animals and other organisms that do not occur naturally in Switzerland but which have been introduced by humans. Many plants and animals brought here in the past have integrated into the ecosystem without apparent negative effects (for example the mandarin duck or the Persian speedwell with its blue-purple flowers).

However, some imported plants and animals can become a problem: they can cause health problems for humans and animals, cause economic damage such as crop losses or endanger biodiversity. These species are also called «invasive species».