The most versatile summer vegetable I can think of is onions.  Sweet onions, like Vidalia are abundant in summer months.  Onions belong to the same family as garlic, leeks, chives, scallions and shallots. 

They are rich in thiosulfinates which exhibit antimicrobial properties.  This means they fight against bacterias like Salmonella and E. coli.  They have a variety of medicinal uses.  Early American settlers used them to treat coughs, colds and asthma.

They also contain a number of sulfides which control blood pressure and protect against cancer.  In central Georgia, the home of the Vidalia Onion, mortality rates from stomach cancer are half that of the average for Americans.  They also contain anti-inflammatory agents.

Choose onions that are clean with crisp, dry skins.  Store them at room temperature away from bright light.  After cutting, wrap tightly and store in refrigerator for 1-2 days.

Onions can be eaten raw in salads and salsas.  They can be sauteed and added to soups, vegetables and stir-frys.  My favorite – battered and fried in onion rings.