In order to know when you should throw away your memory foam pillow, you need to know what they are made of. Memory foam pillows are usually made from polyurethane, which is a type of plastic that releases hydrocarbons when it breaks down. Memory foam pillows have been found to contain cancer-causing agents called phthalates. They also contain toxic chemicals like formaldehyde and benzene. This article will go through the lifespan of a memory foam pillow and how it affects your health.