Saw palmetto doesn't work, although unlike some herbal remedies, it doesn't directly do any harm either. It is usually used in an effort to treat frequent urination in men.
WIC (Women, Infants and Children), a government program that distributes infant formula to the poor (among other things) has participants with below average breast feeding rates (10% v. 22% for the general population fully breast feed). Using formula rather than breat feeding is bad for infant health. Breast feeding proponents say this is evidence that WIC is counterproductive. Supporters of the program say that there isn't a cause and effect relationship and blame the low rates on economic pressures to return to work that WIC mothers face.
Taking Prozac in late pregnancy harms infants lungs.
Cancer rates have been falling for some time. Now, for the first time since 1930, raw numbers of annual cancer deaths (for 2003) are down too. A decline in the smoking habit, early detection of cancer and better treatments are credited with the decline.