Marsh thistle originates from marshy environments across major regions of the northern hemisphere, mostly in temperate zones. While native to various parts of Europe and the northern fringes of Asia, marsh thistle has been introduced to certain areas in North America, as well as oceanic and island nations in the Southern Hemisphere.

Marsh thistle poses mild toxicity upon ingestion for humans, cats, and dogs. All parts are toxic, causing symptoms like nausea, vomiting, oral irritation in humans, and similar symptoms plus physical discomfort in pets. Immediate medical or veterinary attention is crucial upon ingestion. Foragers and pet owners should recognize and avoid marsh thistle to prevent accidental poisoning.

Marsh thistle originates from Northern Europe and Scandinavia. This plant is classified as a weed due to its robust reproductive capabilities and rapid, invasive growth. It produces numerous seeds that are easily spread by wind, allowing it to colonize new areas quickly. Marsh thistle can also propagate through its root system, contributing to its prolific spread, particularly in wetlands, pastures, and gardens. Its tall and spiky form can overrun native vegetation, and its extensive root system can deplete the soil nutrients, causing harm to other plants. The plant's tendency to form dense thickets can make it detrimental to gardens, impeding the growth of more desirable plants. Due to these factors, this plant can be a serious threat to biodiversity.

The best season for the removal of marsh thistle is during late spring or early summer. It is crucial to remove the weed before it starts to develop seeds to prevent additional spread.