Ripe tomato
Digital Vision./Digital Vision/Getty Images

If you are sensitive to nightshades, you might feel nauseous, have an upset stomach, get a headache or feel depressed after eating them. Identifying nightshade foods is relatively easy, but avoiding them in your diet can be a bit of a challenge. Processed foods often contain nightshades such as potato, tomato and pepper to improve their flavor or texture. Once you learn which foods you are able to eat, your uncomfortable side effects should disappear shortly.

Do not eat potatoes, sweet potatoes, yams or cassava root. Avoid processed foods that contain these items by reading the ingredients lists. Potato starch is added as a thickener to foods such as ice cream, yogurt, candy and frozen foods. It will often appear on ingredients lists as "modified food starch." Vodka is often made from fermented potatoes.

Avoid eating tomatoes, tomato sauce, ketchup, barbecue sauce and other processed foods containing tomatoes. Manufacturers add tomato powder to many processed foods as a flavoring, and most vegetable broths contain tomato. Tomatillos, often used to make salsa, are also a member of the nightshade family.

Eliminate bell and hot peppers from your diet including red peppers, green peppers, cayenne peppers, chili peppers, paprika and jalapenos. Avoid hot sauce because it is made primarily of peppers. Paprika is often used as a food coloring and additive in margarine, salad dressing, mayonnaise, sausages and hot dogs, soups, stews and spice blends. Peppercorns are not part of the nightshade family and are fine to eat.

Exclude eggplant from your diet because it is a nightshade.

Read food labels to avoid eating tapioca starch because it is made from cassava, a nightshade. Gluten-free products, baked goods, thick sauces and bubble tea commonly contain tapioca.

Do not chew tobacco because it is a member of the nightshade family.

Season food with herbs, onion, garlic, salt and peppercorn instead of using tomato or pepper products.

Tip

Alkaloids are the compounds in nightshades that cause sensitivities and even make some of them -- such as belladonna -- poisonous. Cooking nightshade vegetables reduces the amount of alkaloids and may prevent some sensitivities. The National Institutes of Health also recommends avoiding potatoes that are green under the skin and removing all the sprouts from potatoes before eating them to reduce alkaloid intake.