Nightshade fruits and vegetables belong to the family of Solanaceae plants of the Solanum genus. According to Encyclopaedia Britannica, this group of plants contains more than 2,500 species that are widely used as food and in medicine. Some people have a sensitivity to nightshade plants and are unable to digest them fully. If you have a sensitivity, you may experience diarrhea, gas, bloating, nausea, painful joints, headaches and depression from consuming nightshades.
Here’s a list of the most common nightshade fruits and vegetables found in different diets across the world:

POTATOES Potatoes are part of the nightshade family. This includes white, red, yellow and blue-skinned potato varieties. However, sweet potatoes and yams are not nightshades, according to The Weston A. Price Foundation. If you have allergies or sensitivity to members of the nightshade family, you need to avoid foods made from potatoes – potato salad, french fries and mashed potatoes being 3 of the most popular potato dishes. Also, be sure to read ingredient lists on all processed foods to avoid potatoes and potato starch completely.
TOMATOES Another widely consumed member of the nightshade family are tomatoes. Although the culinary world refers to tomatoes as vegetables, scientifically, they fall into the category of fruit. Stay away from all raw tomatoes as well as from cooked ones in other preparations like tomato sauce and ketchup. Be sure to read the ingredient lists on soups and condiments including salsas, hot sauces and marinades, because they often contain tomatoes also.
PEPPERS All peppers belong to the Solanaceae family. This includes bell peppers, jalapenos, habaneros, cayenne peppers and paprika. Paprika, a spice made from ground, dried peppers, is widely used in a variety of cuisines. Be sure to read labels and communicate well with waiters and chefs when eating out to avoid it. Peppercorns are not a member of the nightshade family, even though they contain the word “pepper” within their name.
EGGPLANT Eggplant appears in Italian, Thai, Indian and other ethnic cuisines. Even though you need to avoid eating eggplant if you have a nightshade sensitivity, you can easily avoid dishes such as Eggplant Parmesan. If you’re ordering a meal which states that it contains mixed vegetables, be sure to reiterate that you cannot eat eggplant and other nightshades. When in doubt, avoid a food altogether.
TOMATILLOS Tomatillos, another member of the nightshade family, are often found in Mexican cuisine. The fruit grows well in warm climates and can be found as a wild weed in parts of Mexico. Tomatillos have a papery husk and hang like small round paper lanterns from the plants. When ripe, they’re either pale yellow or purple and have a slightly citrus-like flavour. You’ll often find tomatillos in sauces and salsas, such as salsa verde.
GOJI BERRIES AND OTHER BERRIES Small, red goji berries fall into the nightshade family too. These slightly sweet berries, sometimes called wolfberries, are native to Asia. They can be eaten raw, dried or made into a juice. They’re easy nightshades to avoid, but do read ingredient lists of all juices, smoothies, teas and nutritional supplements to be sure your groceries don’t contain goji berries. Other nightshade berries include garden huckleberries, ground cherries and cape gooseberries, but not gooseberries or regular blueberries.