If your natural nails have turned a sickly shade of yellow, chances are your nail polish is to blame. “If the yellow is sharply cut-off, it is usually from dark polish [staining the nail],” Antoinette Notaro, a dermatologist at Schweiger Dermatology in New York, told YouBeauty.

The solution? You need to give your nails a break, but that doesn’t mean giving up your mani-pedis (especially if you’re an ethical customer) — just take a time out from dark polish for a while. “The treatment is simply to use lighter polish for several months as [the stain] grows out,” Notaro explained.

Other common causes behind yellow nails are an infection or trauma. “If it’s caused by infection, there is often thickening of the nail and “stuff” — we call it subungual debris — underneath the edge of the nail,” Notaro said. “That requires a doctor’s visit to get a culture done, followed by a prescription medication.”

Notaro added: “Obviously, if it’s caused by trauma, avoiding things that cause it is the only way to allow the nail to heal,” she said. However, that’s easier said than done if your workout routine is to blame, such as your toenails banging the front of the shoe during spinning class or while running. It can help if you keep your toenails trimmed and make sure your cycling shoes and sneakers fit properly, keeping a thumb’s width between the tip of your toes and the front of your shoe.

When it comes to growing out a nasty yellow nail, patience is key. “It’s important to remember that fingernails take six months to grow out,” Notaro said, “and toenails can take up to two years!”