Parabens, the synthetic chemicals used as preservatives in foods, cosmetics, and pharmaceuticals, have been the topic of heated debate about whether they are linked to certain cancers. While rodent studies have found that paraben exposure in high doses could cause breast cancer, a recent scientific review in the Journal of the National Cancer Institute concludes that there is no evidence to suggest that using paraben-containing products leads to an increased risk of cancer in humans. Live Science consulted with Associate Professor Biology Gretchen Edwalds-Gilbert, who notes that paraben sensitivity varies from person to person. “As with many potentially hazardous chemicals, different people will have different susceptibilities and sensitivities based on their own genetic backgrounds,” For those worries about paraben exposure, she recommends following the Latin phrase “ne quid nimis,” which means “nothing in excess.”