Aspartame, a sweetener found in many foods and fizzy drinks, might be classified as “possibly carcinogenic” by the International Agency for Research on Cancer (IARC). This means it could have a potential link to cancer, but it’s not clear how risky it really is. Interestingly, other things like aloe vera, diesel, and pickled Asian vegetables also fall into this category. The IARC made this announcement on July 14.

Aspartame is super sweet—about 200 times sweeter than sugar—which is why it’s used in calorie-free sweeteners. You can find it in diet drinks, gum, some yogurts, and popular drinks like Diet Coke, Coke Zero, Pepsi Max, and 7 Up Free. Shockingly, it’s in about 6,000 different food products.

Even though aspartame is approved by food safety authorities, there’s still controversy. The IARC checked out lots of studies on aspartame and its link to cancer. So, while it may be called “possibly carcinogenic,” it doesn’t tell us exactly how risky it is. The IARC and another expert group made announcements on July 14 and published their findings in a journal called Lancet Oncology.