There are dozens of products you use every day and don’t think twice about, but it turns out that some of them can actually be dangerous and, in rare cases, even fatal. This is a message one California mother wants to bring attention to after the tragic death of her daughter.

To strengthen tooth enamel in 11-year-olds Denise‘s teeth, her mother, Monique Altamiranostarted using a toothpaste that her dentist had recommended. Shockingly, this ended in her daughter’s death. Denise, who was severely allergic to dairy products, suffered a fatal reaction to the toothpaste because it contained dairy products.

Because Monique was very aware of her daughter’s allergy, she was always very careful about what Denise was eating. She even read the labels on toothpaste, but saw that they didn’t contain dairy and stopped paying attention. However, MI Paste One, the toothpaste recommended by her dentist, contained Recaldent, an ingredient derived from milk protein.

Monique spoke with Allergic life about what happened, describing how Denise was “so excited to use her ‘special toothpaste,'” but immediately afterward, her lips began to turn blue and she couldn’t breathe. Denise recognized the symptoms and told her mother that she was having an allergic reaction. Monique administered Denise the EpiPen, but it didn’t help. As the reaction worsened, Monique had to resort to CPR while her other daughter called 911. An ambulance took Denise to the hospital, where she sadly died two days later.

The grieving mother explained: “Contrary to what everyone tells me, I feel like I let her down.” Now she hopes to make other parents of allergy sufferers aware of the potential hidden dangers in everyday objects. Monique said: “We can’t bring Denise back, but we can help others on her behalf. We are so grateful to people who take allergies seriously. Denise wanted to change the world, but it’s heartbreaking how she does it.”

Monique’s main advice for parents of children with allergies is: “Read everything. Don’t get comfortable just because you’ve been dealing with it for several years. Don’t be too embarrassed or afraid to ask and make sure the ingredients are OK. Advocate for your child.”