McDonald’s (NYSE:MCD) is in hot waters after several of its salads caused nearly 400 people to get sick with a parasite.

The Centers for Disease Control and Prevention (CDC) said that roughly 395 people have become ill from eating the fast food chain’s salads in at least 15 U.S. states with confirmed cases. The illness in question is connected with the Cyclospora parasite, which causes diarrhea and is spread through fecal matter.

The CDC added that the McDonald’s salads have caused at least 16 individuals to be hospitalized. Most of the cases of illness have taken place in the Midwest, with the company’s headquarter state of Illinois amassing more than half of these cases (202).

The burger chain said that soon after people began feeling ill last month, it has voluntarily stopped selling salads in the restaurants that were affected. McDonald’s added that it has let that salad supplier go and chosen a new one to help protect the sanity of its products.

The U.S. Food and Drug Administration (FDA) said an analysis that McDonald’s had confirmed that the issue was birthed from its supplier Fresh Express. The agency’s analysis discovered that it found traces of Cyclospora in a sample extracted from an unused package of salad mix that contained romaine lettuce and carrots, which had an expiration date that had already passed.

MCD stock gained about 0.5% on Friday