Chemicals used to soften the plastics of some silicone toys. The main purpose of a phthalate is to act as a softener, and they’re commonly found in dozens of products that contain plastics. Phthalates are often abbreviated when listed on product ingredient lists; for instance, dimethyl phthalate is abbreviated as DMP.

Some studies suggest that phthalates may cause reproductive health issues, and some phthalates may be carcinogenic. However, there is no concrete evidence to suggest that phthalates cause harmful effects in extremely low concentrations. Even so, phthalate use has dropped off significantly in recent years due to health concerns.