If you’ve ever spotted a strange pink residue forming around your shower, bathtub, or sink, you’re not alone — and you may have assumed it was just another harmless type of bathroom mould. However, a recent warning from a doctor suggests that brushing it off could be a serious mistake.
This seemingly minor buildup, often dismissed as a cosmetic issue, has now been linked to infections and even hospitalisations — particularly in people with weakened immune systems.
So what is this mysterious pink slime — and why is it appearing in your bathroom?
Dr. Karan Raj, a medical expert well known for sharing health tips on TikTok, recently responded to concerns after a user revealed they had been hospitalized following exposure to pink residue in a shared university bathroom.
According to Dr. Karan, the pink substance often seen in bathrooms isn’t mould at all—it’s actually a type of bacteria known as Serratia marcescens.
“If you’ve noticed this pink slime in your bathroom, it’s not mould—it’s bacteria,” he explained in a video response. “This bacteria thrives in damp, moist areas and feeds on fatty residues found in soaps and shampoos, which is why it’s so common in bathrooms.”
Serratia marcescens produces a reddish-pink pigment called prodigiosin, which gives it its distinctive color, according to Infectious Disease Advisor.
It typically appears in the damp corners of showers, sinks, and bathtubs—especially where soap scum and moisture collect. While it’s usually harmless to healthy individuals, it can pose a risk to those with compromised immune systems or open wounds.
“In most cases, it’s not harmful,” Dr. Karan explained. “But you should avoid getting it in your eyes or into open wounds, especially if you have a weakened immune system.”
According to Infectious Disease Advisor, Serratia marcescens can lead to urinary tract infections, respiratory problems, and other complications in vulnerable individuals. It’s also known to be resistant to multiple antibiotics, making it challenging to treat in clinical settings.
The presence of pink slime may also indicate poor ventilation and excess moisture—conditions that can promote the growth of other, potentially more harmful types of mould. “If your home is damp enough for pink slime to form regularly, there’s a chance you’re also growing actual household mould, which can trigger allergies or respiratory issues,” Dr. Karan warned.
To minimize the risk, Dr. Karan stresses the importance of proper bathroom ventilation. “The first rule of dealing with pink slime is prevention. Keep your bathroom dry and well-ventilated,” he advised. This includes running an exhaust fan, opening a window during and after showers, and routinely disinfecting surfaces.
Regular cleaning with antibacterial products—especially in areas where water collects or soap scum builds up—is also crucial. “It’s not just about cleanliness; it’s about maintaining a safe and healthy environment,” Dr. Karan emphasized.
