Green onions, also known as  scallions or  spring onions, are a favorite ingredient in kitchens around the world. Their crisp texture and mild flavor make them perfect for salads, soups, noodles, and garnishes. However, because they grow close to the soil, they can become contaminated with bacteria, parasites, or other harmful microorganisms if they are not grown, handled, or washed properly. While headlines often exaggerate the danger by calling them “one of the dirtiest vegetables,” the real issue is not the vegetable itself—it is how it is cleaned and prepared before eating.

Green onions spend much of their growing season partially buried in soil. During cultivation, they may come into contact with contaminated irrigation water, animal manure, or dirty harvesting equipment. If proper food safety practices are not followed, harmful microorganisms such as Salmonella, E. coli, Listeria, or certain parasites may contaminate the vegetables.

Unlike foods that are cooked thoroughly, raw green onions do not undergo a heating process capable of destroying many harmful microbes. As a result, eating contaminated green onions without adequate washing may increase the risk of foodborne illness. Symptoms can include nausea, vomiting, diarrhea, stomach cramps, and fever. Most healthy people recover within a few days, but young children, older adults, pregnant women, and individuals with weakened immune systems are at greater risk of serious complications.

Although parasite contamination is possible, it is relatively uncommon in countries with modern agricultural and food safety systems. More often, bacterial contamination is responsible for foodborne outbreaks linked to raw produce. That is why food safety experts emphasize proper washing rather than avoiding nutritious vegetables altogether.