Substituted 2-(2,6-dioxopiperidin-3-yl)phthalimides and
1-oxo-2-(2,6-dioxopiperidin-3-yl)isoindolines reduce the levels of
TNF.alpha. in a mammal. Typical embodiments are
1-oxo-2-(2,6-dioxo-3-methylpiperidin-3-yl)-4,5,6,7-tetrafuoroisoindoline
and 1,3-dioxo-2-(2,6-dioxo-3 -methylpiperidin-3-yl)-4-aminoisoindoline.