Only if you eat them or inhale large amounts of the fumes. Ordinary use of mothballs, such as placing them in an attic or storage chest to protect against moths, poses no risk of toxic exposure.
Mothballs were first made from camphor, and later naphthalene. Today, most are composed of the chemical p-dichlorobenzene. All three substances are toxic to humans if eaten or inhaled in large quantities.
P-dichlorobenzene can irritate you skin, throat and eyes. Prolonged exposure may lead to dizziness, weight loss and liver injury.
