We all know that our pets love to eat human food whenever they get the chance, and while certain foods are actually good for their health, like blueberries and cantaloupe, some can make them very sick or even put their lives in danger. But why are there foods that we can eat that our four-legged friends can’t?

As Dr. Whitney Miller, chief veterinarian at Petco, says, humans evolved differently than cats and dogs, which means we developed different diets and ways of processing food. “From our gastrointestinal makeup to our teeth, we are designed to be omnivores with a rich and complex diet,” she says. “Additionally, our bodies can flush out many toxins that other animals do not have the capability to process.”

To discover some of the foods you likely have at home right now that aren’t safe for your pets, read through this helpful list.

Dr. Liz Moses, emergency veterinarian at Veterinary Emergency Group in Tampa, Florida, further explains that cats and dogs simply lack the necessary enzymes to properly digest some of the foods that we eat regularly. One notable food that’s toxic to cats and dogs is grapes. Although experts are unsure as to what part of the grape is toxic (There is speculation that the skin is to blame.), grapes and raisins can both cause kidney damage and possible failure, according to Dr. Moses.

“Similar to grapes and raisins, we are unclear why Macadamia nuts are toxic to dogs,” Dr. Moses says. “However, they can cause vomiting, ataxia [poor muscle control], weakness, hyperthermia [increased body temperature] and depression.”

Macadamia nuts aren’t the only nuts that are poisonous to pets. Dr. Miller adds that almonds are also toxic.