The most important fruits and vegetables you should buy organic: (1) those with the greatest pesticide residues and (2) the ones you eat most often. Government lab tests show that even after washing, certain fruits and vegetables carry much higher levels of pesticides than do others. Between 2000 and 2005, the not-for-profit Environmental Working Group (EWG) analyzed the results of nearly 51,000 tests for residues on produce. Based on the data, they created a "dirty dozen" list of the most contaminated fruits and veggies.

Top offenders include:

peaches

apples

bell peppers

celery

nectarines

strawberries

cherries

pears

grapes (imported),

spinach

lettuce

potatoes

Always buying these foods organic is ideal, but if you can't, focus on those you eat all the time.