This patent discloses a substituted fullerenes, compositions comprising the same, and their use as antioxidants. The substituted fullerenes comprise a fullerene core (Cn) and at least one of: (i) from 1 to 6 (>CX.sup.1X.sup.2) groups bonded to the fullerene core; (ii) from 1 to 18 --X.sup.3 groups bonded to the fullerene core; (iii) from 1 to 6 --X.sup.4-- groups bonded to the fullerene core; or (iv) from 1 to 6 dendrons bonded to the fullerene core.