These harmless white flowers can cause serious respiratory illness in just anyone

You’ve probably walked past it without even knowing. That bushy, white-flowered weed growing by the roadside, in open plots, or in your garden? That’s Parthenium hysterophorus, also called Congress grass. Looks harmless, right? But don’t be fooled—this green invader is a silent troublemaker. Especially for your lungs.
Let’s break it down and see how this common plant can cause serious respiratory illnesses—and what you can do to stay safe.
is a fast-growing weed originally from Central America. It found its way to India in the 1950s and has since spread like wildfire. It's now one of the most hated weeds in the country. You’ll see it sprouting along highways, railway tracks, farmlands, parks, and even in cities.
The worst part? It releases a toxic chemical called parthenin, which can seriously irritate your skin, eyes, and especially your respiratory system. So even if you’re not touching it directly, just breathing in the air around it can be enough to trigger health problems—particularly if you're allergic or have asthma.

Here’s where things get serious. When Parthenium plants bloom, they release pollen grains and fine airborne particles that float around in the air. These can easily be inhaled by people nearby. For someone with a sensitive immune system or a history of respiratory issues, this can spell trouble.
Some common respiratory issues caused by Parthenium exposure include allergic rhinitis (sneezing, nasal congestion, and runny nose), asthma (wheezing, breathlessness, chest tightness), chronic cough and throat irritation and sinusitis and post-nasal drip. In severe cases, hypersensitivity pneumonitis – a lung condition where tiny air sacs get inflamed, making it hard to breathe.

You might think it only affects people who work outdoors, like farmers or gardeners, but that's not true. Even urban dwellers are at risk, especially during windy seasons when pollen spreads easily.
Parthenium doesn’t discriminate, but some people are more vulnerable than others people with asthma, bronchitis, or a history of allergies; children and elderly, whose lungs are more sensitive; gardeners, farmers, or outdoor workers who come into regular contact with the plant and people living in areas where Parthenium grows unchecked.
If you've been sneezing a lot lately, have itchy eyes, or feel breathless for no obvious reason, you might want to check if this weed is lurking near your home or office.
Not everyone reacts the same way, but here are some warning signs your lungs might be reacting to Parthenium:
If you notice these symptoms flaring up around the same time every year (especially post-monsoon), Parthenium could be a hidden culprit.
While you can’t completely control what grows in public spaces, you can take steps to protect yourself and your loved ones. Avoid direct contact with the plant. Don’t try to pull it out bare-handed. Always wear gloves, masks, and long sleeves if you’re removing it. Keep windows shut during early mornings and evenings when pollen levels are high. Install air purifiers at home, especially if someone has asthma or allergies. Use saline nasal sprays to rinse out pollen from your nostrils. If you’re already allergic, antihistamines or inhaled corticosteroids prescribed by a doctor can help manage symptoms. Push for community clean-up drives. The best way to manage Parthenium is to prevent its growth. Local authorities can help remove infestations from public places.
Parthenium may seem like just another roadside weed, but it's more dangerous than it looks—especially for your lungs. It’s like that silent guest who overstays their welcome and turns your health upside down. The more you know about it, the better prepared you are to fight back.
If you or someone you know has been having unexplained breathing issues or allergies, don’t just blame it on the weather. Sometimes, the culprit is growing right under your nose—literally.